I'm concerned about going with reduction pulleys for especially A.C. cause I live in so. Fla and alternator cause I have a 1000 watt amp. How much HP can I get with just a stock lightweight crank pulley and is this even available for RX8?

 

Ya I have Agency Power underdriven pulley..... all it does is look blue

 

K cool well so far I only have KN&N kit and greddy muffler...Jus looking for somethin simple to do myself for maybe 5-10 horse??? Any suggestions?

 

BHR midpipe can maybe get you those numbers. But it's pricey for the gain you get.
Also, going with a Cobb AccessPORT with a proper tune from MazdaManiac will solidify those numbers.
Check the stickies in the Aftermarket Performance Upgrades section. That'll answer some questions for you...

 

Bling thing only and I wouldn't bother. And................yes, I am in Florida and also have the UR pulley set.
Money is best spent elsewhere.