E46 M3 prices from cars.com :
Progression of M3 power-to-weights over the years : (with the 1M thrown in since it's the real small M sedan of the present)
E30 2865 / 250 (*) = 11.5 (pounds per hp) E36 3220 / 316 = 10.2 E46 3415 / 338 3443? = 10.1 1M 3461 / 335 3329? 3296? = = 10.1 (**) E92 3704-3900 / 414 = 9.2correct/comparable weights are hard to find. Both the manufacturer weights and magazine weights are not reliable. You need the regulatory DIN weight or something but I can't find a good source for that (Wikipedia is no good). Anyway, the details may be a bit off, but the power-to-weights of M cars have changed surpisingly little over the years. The powers have gone up, but so have the weights, only slightly slower.
(* = the E30 S14 engine made more like 200 hp stock, but can be reasonably easy brought up to "race spec"
250 hp using modern electronic fuel injection and a few other cheap mods; unlike the other engines, the S14
was actually raced and is reliable even at higher output).
(** = the 1M can easily make 380 hp or so with standard turbo mods).
Before about 2001 the US versions of most BMW's were crippled. Either worse versions of the engines or completely different engines.
The Z3 "M coupe" shooting-brake is supposedly one of the best handling cars ever made (up there with the NSX and I'm not sure what else). The good one is the late model 2001-2002 which got the E46 M3 engine. Unfortunately the public has figured this out and they're now a bit of a collectors item for enthusiasts; prices have stabilized in the $30k-40k range, around double prices of the earlier small engine Z3 M Coupe. I'm a big fan of how ugly it is, and I love that it has the practicality of a wagon, but I hear the cockpit is a bit small.
The later M coupe is extremely comparable to a Cayman :
E86 Z4 M Coupe (2006-2008) : 330 hp, 3200 pounds = 9.7 (pounds per hp) 997.2 Cayman (2009-2011) : 320 hp, 3000 pounds = 9.4The M Coupe makes better noises and the engine is easier to tune up, it's also more analog, more raw. The Cayman actually has a lot more cabin room and luggage room ; the M is rather uncomfortably cramped, and I didn't love the feel of sitting over the rear axle in a car with a huge hood. The M will certainly depreciate less, and is marginally less douchey.
There's a large spec E30 (E30 325i) amateur race class. It's a very cheap race class to get into with a very strict spec, it looks like a lot of fun. Maybe I'll do something like that in my retirement. Cars like that are called "momentum cars" by racers because they have very little acceleration; not much fun on the street, but they can still be great on a track because it takes a lot of skill to get the right line to keep speed through corners in traffic.