BMW use LUK clutches in the E46, and clutch kits are £202 with the 67% off applied at ECP at the moment. Might be wise pre-empting the replacement and buying now at that sort of price if you know you'll need one soon?
Typical life depends on how the car has been driven, I know mine has lead an easy life mechanically, and I'm not expecting to need to look at replacing it until 100K miles at least. I'll see what the indy says when they take a look at it during the next inspection service.
Capability and character are obviously two different things. For me, the E46 M3 is a balance of both - it has bags of character, is great to drive and has a good amount of power. We all know character comes from flaws, and sometimes you can get bored with "character" and want something that works impeccably. Sometimes, it's vice versa. For me, it is as below:
The E30 M3 has bags of character - but it's not capable at all, and I bet not much fun to drive as a result.
The E36 M3 has less character but has an engine more befitting. It still wasn't a "great" M Car though.
The E46 M3 - as above. The engine, the looks, the refinement without being overly refined just make it a great all round package.
The E92 M3, an glorious engine, hugely capable, but it's getting a bit big and heavy now. Still would have one in a heartbeat though, if nothing else, for that engine.
The F30 M3 - it looks beautiful, aggressive and with an excellent engine which is monsterously fast and versatile - but I think this this has robbed it of character. It's the first M Car that has made me think "Hmmm, would I have it? Or would I check out to see what the competition have to offer." I guess would still have one, but it suffers from the 335i effect in that's it just too good for it's own good and its only flaw is that it's got no flaws. I also think it's just got too much power. 450bhp for a road car is just mad and the only place you could really push it is at a track. But are you going to want to take your £60k car to a track? Some will - most wouldn't.
It all comes back to fun. Having got the Mini, it's reminded me of this. I even think my E46 M3 is too fast to properly exploit, as I can be well in three figures before I know it. The Mini with it's 170bhp and lightweight is hugely fun - and I think this is the future for me. It's easy to see why so many people by MX-5s.
Every time I read or watch something about the E30 M3, I always see the same trend. Those owners/reviewers say it lacks the power, but makes up for it by being an utterly fun car filled with character. I think that's the whole premise of it, and the reason why the E30 has loads of motorsport history behind it. It was very capable for its time, but not in the same way the E46 M3 is still very capable today it seems.
I agree to the most extent that the E46 M3 might have a bit too much power to be able to exploit on the road. But I think for the weight of the car, it's got an engine that completely suits it. But as you say, you can never fully exploit the power all the time, at least not legally anyway.
That's one of the reasons I got the Eventuri, the induction noise from 3000-4000rpm is addictive, and eggs you on to stay in that range just to hear the noise. So you're not really going too fast, but not dawdling about either. On the motorway it's the exact range you're in when cruising along in 6th and applying mild throttle to overtake. Feels good man
Before the Eventuri, I wanted to explore redline more often just to hear and feel the engine noise, but now the mid rpm induction noise is just as satisfying. I think we talked about this before, and pondered why BMW didn't just put the better intake on all M3s to begin with.
In the newer models, things are subdued, and almost too refined (hence the lacking in character). I think the designers in many ways have made up for that in making a design that visually makes up that character to the most extent. They do look great! Whereas the older cars only got more and more lary as the rpms went up, even though they looked less in your face on the outside.