My bike that I bought used has those fitted by the previous owner. I haven't been riding it yet though (long story for that). I have heard them though and they sound great!

It's a fullsystem by a high-qualitymaker so I guess you can't go wrong with them. Since it's a 2-1 you save some weight too and they are made out of stainless steel.

Some more info for you can be found here:

http://www.gpr.it/prodotti.htm?idTip...&idMod=&idAcc=