Fault diagnosis: Forza West or Clayton Cars

[carreauchompeur]

Folks,

I need some diagnosis on my E36 M3. No fault codes, but a bit lacking in power and I think either the VANOS seals need redoing or it's the MAF sensor, or indeed something completely different.

Anyone with experience of the above 2 places? I don't want them just to plug it in, find no codes and then charge me anyway. It needs a bit of knowledge of old beemers!

Cheers

[carreauchompeur]

Noted all, many thanks- Forza it is.