Quote Originally Posted by John Jones Jr. View Post
Dok, a few question for you if you don't mind.

I fitting my new over sized next week, should I fit the M5 MAF too?
What I'm concerned about is the engine running too lean ( I've no way of checking the AFR) and I've have read some horror stories on one or two SLK sites (of course among positive stories also) about just fitting the over size pulley.

Are you fairly sure I don't need to up the fuel pressure and run cooler plugs?

Also, how necessary is it to have the engine remapped?

Thanks in advance.
If you have a good MAF, then I see no reason to fit the M5 MAF. As krumb pointed out, the knock sensor will prevent detonation by retarding our timing.

You don't need to up the fuel pressure. But fitting colder plugs would help for performance.