Some of dual stinger exhaust are the best you can buy, but just because the exhaust flows more freely doesnt mean it gives you more power. Some back pressure is needed(not just for the tank pressurizing effect) but for more torque and such.

But do not by the Super Charger, these are two strokes, the exhaust port is open before and after the intake port closes. It sends the charge right out the exhaust, so no extra power is added at all and the only real thing that it does is send fuel into the exhaust. Which is nothing but a waste of fuel, unless you like wasting fuel at $25 a gallon. Now the nitrous doesnt work like you think it will either.

Nitrous is an oxidezer all it does is add more oxygen so that more fuel may burn, now the thing is you would need to run your engine extremely rich so that you may get any benefit from the nitrous. If you dont run the engine extremely rich you will cause on over lean condition within the enigne that will burn the engine up just after several uses that add's no power at all and destroys your engine. Now you can run it extremely rich so that you do get the benefit from the nitrous. But as with the Supercharger you will just waste fuel when not using the nitrous and the enigne will be so pig rich that the engine will barely run and have any real performance.

The best thing you can do is to port your engine or smooth so some other type of internal engine work. But dont step right into it and start doing port work. Cause if you you can easily go a little to far and take the port timming to far that will make the engine either run poorly or not run at all. Do some reading, do a search there are tons of threads about porting these engine's. But you can also run more nitro like 30% if your running 20% and such. Or you can run a hotter plug then you currently are.