two brother M-7 exhaust for bottom to mid increase?

[cbr929rr]

I'm looking for a quiet exhaust and two brothers has been measured multiple times at 91 db with a quiet core. Has anyone used one, are they any good. I'm looking for more bottom and mid power and i think that may work well with the backpressure from the quiet core, they look nice too. My only other consideration is a dubach dr. d exhaust with a quiet core at about 93 db on a yamaha yzf450 so it may be quieter on a 400ex.

[400eXr1d3rZ]

yoshi with quiet core, or white brothers with no disks, just the plate, its quiet as stock, and give alot of bottem