I think the powerflow centres vary a lot and it depends whos building it.
There are plenty of custom exhaust makers about that's make a great job, a bit of local research should yield results!
I've personally seen Mikes K2 and I wouldn't have been happy with it either. I've seen others though and they've been spot on, Japspeed have offered a brilliant group buy price and money back if the fitting is not right so that's a good thing! I agree that the K1 is too loud for my tastes.