It depeneds on whether or not you can afford "service after the mods." when you start making something go significantly faster than it was designed to be things will start to break. Go ahead and ask every racing team ever if you need confirmation of that fact.

Bottom line, if you love your E and don't plan on parting with it, and have the dough for mods as well as fixing things thatb break... Then hell yes. Modify the **** out of it and stick on an E 320CDI badge