There are several forced induction kits for the 3.2L, but they cost about 10k. Kleeman makes one... You could also swap in a supercharger from a SLK32 AMG MB for example, but you would almost need to do an entire engine swap because you would need the lower compression pistons and added strength. I am pretty sure it is the same engine that came in the SRT6 Crossfires...

I am going the Nitrous Kit approach. You can keep your fuel efficiency and driveability, but get SRT6 power for a fraction of the cost.
I think I am going to start with a 100hp wet kit and move up to a 150hp. I know there are some guys on MB forums that run 150 shots on the 3.2L...
I'll take alot of pictures as I install my kit on my '99 CLK320 and post 'em up if anybody is interested. Speaking of which, does anybody know where I can get a cheap upper intake manifold?