SHOShop's y-pipe eliminates the actual y-pipe and just feeds the two exhaust manifolds into a dual-inlet cat. Can't recommend it though, as I believe that eliminating the 180-degree bend lost power on the dyno. Better off going with the MSDS headers and y-pipe combo. I think those run around $500.
The y-split in the rear could use an improvement. All the aftermarket cat-backs have different but better setups. Might want to see if Leonard's can copy them or something.
