dont know about the # but i love the sound of the "quiet" baffles on most aftermarket pipes the are not much quiter but really cut the higher pitched tinny sound leavin just the low notes.
Have the Rinehart quiet baffles in right now. Gave up 8hp. and 10 lbs/ft. on my 95" cammed and ported, 10.5/1 streetglide. On a stock motor I would expect 3-6 hp/tq at most but remember there would still be much more power than stock. Obviously it doesn't run better or have more torque (sheesh, where do they hear that stuff?) but they still have that great Rinehart crackle and run quiet 'til you twist her open.