I believe E46 M3s dyno somewhere in the 270rwhp range while stock 350Zs (older ones, not sure about the new ones) dyno somewhere around 230whp with similar weight.

I saw 2-3 different 350Zs dyno at a Main Stream dyno day between 225whp and 235whp. Granted, this was 3 years ago so I don't know if the new ones make anymore power.