Yes, yes, this isn’t a fair fight. It’s 2 Series versus 3 Series, it’s a £60k car from 2003 against a £60k now, and the very first iteration of an M car against the ultimate evolution. But hey, when you get access to a CSL and an M2 at the same time, you make something happen. We’ll do 1M and M2 at some point in the future, for sure. There’s a link between E46 and G87, too, as end-of-era cars. The CSL was the ultimate naturally aspirated, straight-six M car, the configuration most famously associated with the Motorsport BMWs; 30 years of them reached their zenith with the grey car. And now we have the final non-hybrid M car, with everything from now on to be electrified; not the final version (at least, hopefully not), but a pretty significant milestone nonetheless.

To drive an M3 CSL has been a dream for 20 years now. On the brink of adolescence and with some idea of what cars I really, really liked, 2003/4 was an unforgettable period. It only seems more special now. As well as the coupes (350Z, RX-8, Monaro) and the hot hatches (Focus RS, 147 GTA, Clio V6 255) and many, many more were the road racers: cars like the 360 Challenge Stradale, first 911 GT3 RS and, of course, the CSL. A lighter, louder, more powerful, more exotic version of one of my favourite cars, I was obsessed. How obsessed? I had induction noise recorded off a Clarkson DVD to wake me up for a paper round. And you thought you were a weird kid…

So there was some excitement. And perhaps because of that, perhaps because of the cult status, and perhaps because of the values now attached, driving an E46 CSL was a mixed bag. Of course, the engine is utterly sensational, a reminder of just how intoxicating a great atmospheric power unit can be; 360hp still feels fast 20 years later, and the throttle response is out of this world. The sound will live with me for a very long time indeed. It didn’t take long to be reminded why the S54 is so universally adored.

Plenty more of it is fairly glorious, too. Of course, the BMW balance is spot on, aided in this instance by compact dimensions and sensibly sized tyres (including a rear Michelin narrower than the front M2 rubber). It’s confidence-inspiring from the off, which is always nice when somebody has lent you their precious old car. And, of course, the CSL looks glorious: the wheels, the roof, the bootlid, that gaping intake hole in the front bumper still complement the E46 M3 absolutely perfectly. There’s never going to be a day that the CSL doesn’t make you stop and stare. Especially when the alternative is a new M2. Even as a fan of the 2 Series, the old stager doesn’t show it in a favourable light.

But, objectively speaking (and in the harsh light of 20 years later) the CSL is some way short of perfect. Adult me was a little disappointed; 13-year-old Matt was devastated. The SMG really hasn’t aged very well at all – it takes all of three auto gearchanges to understand why these are being swapped out for a manual, seemingly in their droves. You can get around its flaws, but what a shame this couldn’t have come from the DCT era. A paddleshift does play well to its track-focused nature, but a gearbox that wasn’t amazing in 2003 really can’t cut it nowadays. Pity. How a car of this nature was launched with such woeful brakes is a mystery, too. And while we’re used to raving about old car steering, I’m not sure the rack of the CSL – quicker than a standard E46 – is any great paragon. It’s a lovely old M3, I think, but would struggle to part with what’s now being asked for them. At £50k or so they were intriguing modern classics; now they feel like an awful lot of money for the experience on offer. Sorry guys.

The fact that the M2 still felt exciting after the CSL bodes very well, I think, for the future of what seems to be a divisive model. Inevitably it’s a less delicate driving experience than the M3, but that could be said about any car against something like its 2003 equivalent. You’re inevitably a little more detached from the action, but there’s still plenty to enjoy here. The immediacy of the front end is a revelation against the old car, and while there’s undoubtedly a lot more purchase, the fact that there’s so much more torque from the S58 means it’s some (long) way from one-dimensional. Even on the standard brakes, it stops brilliantly well. Yes, it’d be nicer if the smallest M car was a bit more compact, and it’d be wonderful if every new BMW could sound like a CSL, but given how broad the new M2’s remit must be I think it’s a really impressive thing.

Moreover, while this wasn’t a conventional twin test, having CSL together with M2 made me a bit more optimistic about the future. No, an end-of-the-line special for this M2 won’t look as pure or sound as wonderful as an E46. And no, it’s not going to be a cheap car, either (but then neither was the CSL). All that being said, the standard G87 is a great base from which to work from; BMW has shown with recent CS models that it can really work some chassis magic, too. A two-seat, 500hp, manual M2 CSL could (and should) be a fitting farewell to purely combustion M cars.

Engine: 2,993cc, twin-turbo, straight six
Transmission: eight-speed automatic, rear-wheel drive
Power (hp): 460@6,250rpm
Torque (lb ft): 406@2,650-5,870rpm
0-62mph: 4.1secs
Top speed: 155mph (177mph with optional M Driver’s Pack)
Weight: 1,725kg (DIN)
MPG: 29.1
CO2: 220 g/km
Price: £64,890

Engine: 3,246cc 6-cyl
Power (hp): 360@7,900rpm
Torque (lb ft): 273@4,900rpm
0-62mph: 4.9sec
Top speed: 155mph
Weight: 1,385kg
MPG: 23.7
CO2: 287g/km
Price: £58,455 (2004, £100,285 in today’s money)