more power?!?

i chaged my exhaust from my rx-8 and it is a difrence,a small one but there is.i race my mazda here in romania and i am pleased.of course i want more power but for the moment there is no one who can make the electronics for this cars. i gain fron the exhaust about 10 hp but i chaged the whole sistem from back to the catalyctic converter.the dealer from mazda told me thea i will lose the warranty if i changed the catalyctic converter but but with those things down i will gain 25 hp so friends with the exhaust 10hp and the k&n typchoon air filter 9.5 hp there is aditional power.but i need more ,and i descoverd turbo for rx8 but the price is verry hight $6250.http://www.speedforceracing.com/index.php



some engine electronics can it be done??
i have a friend with an audi a3 18turbo 180 hp and he changed the softweare and now he hase 240 and he is better than me
my mazda haz also 240 but that turbo of his makes the defrence.
so what can i do ??????
can i have more hp from the electronics????