Its an Apexi. Was on the car when I bought it 3+ years ago. I like it actually and probably will keep it (considered upgrading to Twin 2 or such...). It is very quiet cruising along though has a nice burble at idle...but under WOT - watch out - it wails with the best of them! Sounds pretty wicked. Has caused my passengers to laugh diobolically and comment how other drivers around me must be p*ssing their pants (as I fly up on and around them)!