Trusted M specialists are often hard to come by... Last week I used RD Motorsport as recommended by others on here. They are at Newbridge Roundabout in Edinburgh. Had my E46 M3 in for Cylinder Head Gasket repair, Vanos checks, and a few other engine parts. Cannot recommend highly enough. Kept me informed throughout and sent a load of photos of the work as it was ongoing. Rob is very knowledgable and knows these cars inside out. He has a genuine love for M cars
I've just had a look at his facebook page and his latest post is about replacing the rod bearings on an e92 M3. Good to know there could be someone to do that kind of work up here.