It has that sound, because it has dual exhaust. Slants respond and sound better with an HP single exhaust. Either port a stock manifold outlet to 2.5" and go that all the way out, OR run something like the Dutra Duals, or 3 into two headers. Then merge them into one big pipe just under the driver's seat. This will give the best scavenging. It'll sound better, too.
