but greg d's supersplits are proven to add more power. if you get any downpipes get thoes. and match it up with a 2.5 in testpipe. but dont get the 2.4 even the z1 2.4 are thoes cheap chinese brand. you can see them all over ebay and else where they cost nothing to make. thats why Z1's 2.5 test pipe costs alot more and has better bends. but if your getting the exhaust just get everything from greg he might be nice and do a package deal and save you some money :)