Thanks guys,
The RS4 does indeed sound nice, but I love both V6 and V8 sounds equally. Not really sure how to explain it but they each have their own unique character and I don't find the V6 inferior just because it has less cylinders. The standard R32 sounds a lot nicer than a standard M400 in my opinion. Modified exhausts give the M400 a better sound but even then, a milteked R32 is hard to beat.
I guess a miltek may well be my first mod, although I don't tend to mod an awful lot.