That's at a whole different level than what I am doing. The problem mainly is the wiring harness. If you wanted to go "bare-bones" it wouldn't be too bad. But if you wanted everything to work, properly, you're talking many, many hours of work. I contemplated doing it to my ZHP and realized what a ridiculous idea it was and bought an M3. I suggest selling the Z4 and buying a Z4M. Yes, initial cost is more, but the time and money (because it will be more than you think) you save is well, well worth it. If they didn't make a Z4M I would say do it, but they do, so don't. Not trying to curb your enthusiasm, but it just isn't worth it. Last, think of re-sale value, it would be a lot less than what you put into it.Will you help me swap a s54 into my z4 coupe?