Originally posted by SQPlus:
True, you do need a higher flowing exhaust to get the full benefit of that intake. But you can install it on a stock engine and still see gains. I'm pretty sure that zx2 had an accel coil and a different muffler. So, I doubt you'll see the gains they did if you install it on a stock engine. 
The ZX2 that was tested was all stock except the coil and wires. The ignition gains almost nothing so most of the gains on that vehicle were from the intake kit. The exhaust was stock too.
