I think the real question here should be what DO YOU want, and how much are you ready to spend!
When you have deep pockets, you can go buy an M5/M6, or a blown M3, or OR get something crazy build like a V10 E30!!! The sky is the limit of what can be done, the only limiting factor for most people is $$$. So if you have the money, it comes down to what you want in a car. HP is just a #, what car its in makes all the difference.