I too have read that the US version 560 hp is underrated. Would be interesting to see a verification of this.

Also, besides emissions and exhaust changes, doesn't the Euro 560 have bigger pistons?

I don't think you can efficiently Euorize a US spec 560, better of just getting a euro 560 V8.

"stummala" has some neat ideas at
http://www.mbcoupes.com/