I would start with the clutching. make sure every thing is aligned properly to ensure that you are getting full shift from your clutch. heelclickers would be your best bet, there expensive but well worth the money. as for the pipe there are tons of aftermarket pipes available but i would first invest in an egt gauge to measure exhaust gas temp.
1280F is the optimum temp you want to run at more than that your running to lean less than that your running to rich thus robbing horsepower and maybe damaging your engine hope this helps.- somewhere i have some info on this subject if you want send me your e-mail address through the private post and i will send it when i find it (ill look tonight)- craig