Does anyone know if those two are a good combination, or would it rob me from my HP and torque. Also does anyone know if the Axleback gives off a good growl? thanks.

 

Its a good combo. Exhausts and Headers Compound each others gains. Magnaflow give of a decent tone. And if RRM is bundling the packages together then it should save you some coin on shipping.

 

Yes you should have pretty good results by combining the two... and if you add a CAI your results will improve greatly beyond that. Each works to improve air flow, but when used in conjunction, each ones air flow is maximized for best results.