I ran my DWG with SE-2 slip-ons only with no problems and this was in the dead heat of a Texas summer. I installed a PCIII when I upgraded to a Ness Big Sucker AC.

 

So far it seems ok to me. I get a little popping on decelleration but no backfiring or other assorted ugly sounds. Bike still seems to run a little rich to me but it was like that out of the crate. I was hoping the more open pipes would cure that. They sound real nice to me with a good n loud sound but not so loud the cops are eyeballing me everytime I goose the gas.

I got these pipes through an indy guy around the corner who went through Drag Specialties. Part # MS-129
http://www.dragspecialties.com/fatbook/10/143/3873528

 

I put the V&H slipons on my '07 Superglide and nothing else. Ocassionally I will get a decel pop but that is it. I personally don't do long decels so I don't know about that.