If you want loud do what I did; Japspeed K1 and Berks decats, it is loud but means I rarely get people tailgating me now as it makes their car vibrate lol
It can drive you nuts if you just want a "quiet" drive, but I just put the bungs in (particularly when leaving early morning or getting home late as I quite like my neighbours!), it has an awesome rumble when shifting down gears or just letting the engine slow itself down rather than braking. If you can't handle vibrations its not the one for you (everything vibrates and I have the rear sound deadened lol). Accelerating slowly uphill is the worst and the droning can be pretty harsh but I'm used to it and it doesn't bother me, hard accelerating at Santa Pod it sounded amazing, but I do tend to say she's "all mouth, no trousers" as it sounds like its going a lot faster than it really is lol