After a bunch of reading here on HDF regarding the V&H QBs, I gotthem for my '07 FLSTSC w/V&H Fishtail II slip-on mufflers. They now sound almost exactly like the Samson Silver Bullet fishtails I had on my '97 FLSTS (which is a good thing...I always thought they sounded great.) With the stock baffles, the V&Hs sounded kind of like a drag bike...too much high-pitched "clatter". The quiet baffles attenuate the higher sounds and leave the rumble. My wrench said they probably wouldn't require another re-map, and it runs fine (I was getting some popping on upshifts, which is now gone.)

 

just ordered V&N slip ons for my fatboy and a set of quite baffels, do the baffels make a lot of difference, are they very loud

 

I really like the quiet baffles so far. They have that classic Harley sound, and they aren't all that quiet. Try the mufflerswith the regular baffles first, then the QBs. You can always change them back if they are not to your liking.