When I rev over 4500 in the first few gears I can hear a loud squeeling sound, sort of like the squealing belt in my old E30 325. I know this isn't a very detailed description, but anybody have any thoughts?
have you checked for loose belts? When I replaced mine they stretched a bit after a few days causting the alternator belt to loosen enough to squeal at just about the same revs as you describe.