The engine may well be the same but the dme and traction control systems are quite different. The TC in the m3 is significantly cruder than the z4m.ph001 wrote: ↑Wed Sep 05, 2018 10:36 am..don't get this at all, it's the same S54 engine but the exhaust is slightly more optimised on the E46. It's darn near instant, not sure how you could ever get much better without a much lightened flywheel (and the associated stalling when setting off issues).
Similarly the throttle maps in both cars as standard are very different, the m3 having a far more pronounced dead spot at the beginning of the throttle travel as dgm points out.
Many m3s by now will have been modded by a dme tune such as ecuworx to get rid of this which might explain why some don't feel this, though it's not clear to me whether these people have actually driven a z4m to compare it to.