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BMW M135i v Porsche 997 Carrera 3.6: Old or new?

BMW M135i v Porsche 997 Carrera 3.6: Old or new? Classic and Performance Car

The BMW M135i represents a great value performance buy, but could you afford to run a used Porsche 911 for the same money? We find out

Old or new? That’s the question. Simple maths show that if you buy a slightly older performance car, there is scope to run something far more exciting for around the same money as, for example, a brand new hot hatch. 
With that in mind we’ve paired-up two cars that cost roughly the same upfront, offer practicality and performance to varying degrees, however approach the goal of driving enjoyment from very different starting points. The aim is to explore the real-world costs involved in running both over a three-year period. 
The recently facelifted BMW M135i is still near the top of its game in the hot hatch sector with class-leading performance and a cracking rear-wheel drive chassis. It’s is a desirable car in its own right, but if we said you could buy a 997-generation Porsche 911 Carrera for the same price, you’d surely be just a little tempted to find out how much it would actually cost to run. 
There are a few things to consider before diving in. Running costs on older cars are inevitably going to be steeper (especially with more exotic machinery), technology has moved on quite a bit in nearly a decade and certain equipment that is now commonplace in an entry level Fiesta was not even an option in the 2000s. So let’s take a look at the two contenders and see how they stack up.
BMW M135i: The sensible choice
The M135i has been around for a few years now, the success of the previous shape 135i Coupe no doubt ensuring it would be an integral part of BMW’s line-up for the years to come. Combining rear wheel drive dynamics with the compact dimensions that made the 1980s E30 3-series such a joy to drive, the M135i straddles the gap between the mainstream 1-series and the proper M cars. 
Driving the M135i reveals a car with lag free acceleration, the torque rich delivery really pushes you back into your seat and while it may not have the delicate handling balance of an M car or a 911, at saner speeds it flows down your favourite twisty road with real composure. 
A recent facelift has improved the only real weak point of the current M135i, its bug eyed looks. Small improvements in power and standard Satnav, LED rear lights and internet connectivity round off the upgrades. Basic pricing on a manual three-door M135i with a few must have options comes in at around £35,000. As with any BMW, get too liberal with the box ticking on the options list and you could soon have a £40k hatchback sitting in your driveway. 
A smooth 8 speed ZF auto box and practical 5 door shape are also available as well as many trim and paint options to help you personalise your car. A limited slip differential is on the options list and is a must if you intend to use it for trackdays.  
Porsche Carrera 997.2: The car you've always wanted
At this price point there are a lot of models to choose from, excluding the GT3, Turbo and special editions, which are out of our price range. We can look at the standard Carrera which came in convertible, coupe, hard top and Targa variants. There were two engine sizes and manual or automatic options on offer in each of these body styles. To narrow your search, make sure that you look around for a facelifted model or at least a post-2009 car as these have had some important improvements over the earlier cars. 
Early Carreras suffered from some potentially serious engine issues. It is essential to get the car checked over by a specialist to make sure that any of the common faults that affect these cars have been attended to. The updated direct injection engines seem to be a lot more reliable than pre-facelift cars.
Four-wheel drive may be useful in the wet but it is not really necessary in a non-turbo Carrera. With this in mind, a 3.6 Carrera in coupe form with a manual gearbox would be the purist’s choice, and will definitely become a desirable collectors car in the years to come. The 3.8 adds some more power and PASM comes as standard but finding a face lifted one will be a challenge at this price. The outdated tiptronic gearboxes were also replaced in 2009 by the much improved dual clutch PDK setup. 

You may not get to choose the exact specifications as you would with a new car but most owners would have chosen a sensible mix of options when buying new so the differences between models are not as marked as you would imagine. Satnav is a nice-to-have and the Porsche system is a good one but technology moves on so don’t let a good car go if it doesn’t come equipped with it. 
Enough about the boring nuts an bolts of things, the real reason you buy a Porsche is for the way it drives, and in this regard the 997 Carrera doesn’t disappoint. The familiar flat six growl, sharp steering and communicative chassis all make every drive a lot more engaging than most other machines, especially the BMW. 
Porsche purists will tell you that each new iteration loses some 911-ness, but the 997 is a good compromise between the raw air-cooled cars that would be tiresome on longer journeys and the all conquering 991 models that require you to be at the tenths before they relinquish their grip on the tarmac. A naturally aspirated engine that loves to rev completes the package and is an increasingly rare treat in today’s turbocharged world.
Performance Comparison

BMW M135i Manual 3-door
Engine N55 3.0 Litre 24-valve I6-Turbo 
Power 322 bhp @ 6600rpm
Torque 332 lb ft @ 1300rpm
Top Speed 155mph (limited)
0-62mph 5.1 seconds (4.9-auto)
Consumption 36mpg
Gearbox Six-speed manual/Eight-speed auto

Porsche Carrera 997.2 3.6 Manual 2009 
Engine A91 DFI 3.6 Litre 24-valve H6 
Power 345 bhp @ 6800rpm
Torque 288 lb ft @ 4400rpm
Top Speed 178mph 
0-62mph 4.9 seconds (4.7-PDK)
Consumption 29.4mpg
Gearbox Six-speed manual/Eight-speed auto
While on paper the numbers are very close, the Porsche delivers its best at higher rpm while the BMW is happiest relying on its superior torque lower down the rev range. This means that the BMW will be more at home in cut and thrust driving while the Porsche will be more rewarding on roads where you can access its stronger top end. 
Running Costs: What it will really cost over three years 
There are a lot of ways to purchase a new car these days and the most cost effective option will depend on how much you want to put down up front as well as whether it will be a personal or business purchase. For the purposes of this comparison we will keep things relatively simple and assume that the buyer is a 35 year old male with a clean driving record, is willing to put down a 20 per cent deposit, will pay the car off after 3 years at 6 per cent interest and wants to keep it after the finance period is over. Average mileage will be estimated at around 10,000 miles per annum.

Porsche Carrera 997.2 3.6 Manual 2009 

Purchase price £35,000
Deposit £7000
Repayments £849 p/m
Interest Portion £2564 over 3 years
Insurance  £1000 p/a
Servicing £2000 p/a
Fuel costs £1843 p/a
Depreciation  £2500 p/a
Road Tax £290 p/a
MOT £56 p/a
Cost over 3 years £53,131 – excluding depreciation
Car value after 3 years £27,500
Total cost of ownership £25,631
BMW M135i Manual 3-door

Purchase price £35,000
Deposit £7000
Repayments £849 p/m
Interest Portion £2564 over 3 years
Insurance  £750 p/a
Servicing £500 p/a
Fuel costs £1497 p/a
Depreciation  £5500 p/a
Road Tax £290 p/a
MOT £0 p/a
Cost over 3 years £46,675 – excluding depreciation
Car value after 3 years £18,500
Total cost of ownership £28,175
If you want the security and technology of a new car without giving up on straight line performance then the M135i is a great option. It rides better on the motorway and uses considerably less fuel overall than the Porsche. However, and perhaps surprisingly, the overall costs work out at £2544 more than the Porsche over the same period. This is mostly down to the massive depreciation that you unfortunately can’t get away from when buying a new car. 
If high consumption around town and potentially high servicing costs don’t faze you then only the 911 will do. It still feels special to drive and retains that 911 charm which will get you up early in the morning to go for a drive with no particular destination in mind. It works well as a daily driver too, with enough boot space for a week away or your monthly shop. We have allocated a not insignificant £ 2000 p/a on servicing as this should cover any larger bills that may come your way, however well cared for Porsches are reliable cars and you may find that the servicing costs are a fraction of this amount.

Words: John Tallodi

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