I have nearly fixed all the problems with this 328, I say nearly because I have a very deep rumbling sound under hard acceleration, most prominant in say 2nd gear but also interestingly whilst cruising at 80mph.
Another strange thing to note, is that when driving over bumpy roads, the same frequency of noise, i.e a low pictched rumbly noise can be heard. It almost sounds like it could be suspension related and when I accelerate hard it vibrates something causing this deep noise.
Has anyone any ideas??