I am wondering if anyone has done things like this with their 330s, and what kind of hp was had.

You know port the heads, change the intake, stuff like that

Very interested in this as well. Did this to my e28 535is and the results were amazing.

It would be a longer lasting alternative to supercharging, less power, but fun nevertheless. And you could supercharge it as well

i'd love to do all this stuff, but cost is always the determining factor. i'm doing all bolt on mods i can before i consider doing anything nitty gritty like this. and if i do it, i'll wind up saving for another motor, so i can rebuild it.

Doesn't this process cost quite a bit???

Doesn't this process cost quite a bit???

Haha, yes very much so indeed it sucks sometimes but then when i get behind the wheel of my BMW im just like ahhhhhh....just remember it could be worse you could be getting into a honda instead....think of it that way.

well I know for my m54 2.5 engine bigger valves where not made. but they did clean everything up and some other stuff to my car which came back with a little more low end power and a deeper tone.