just tell me if 420 $ for remove resonator and go with straight pipe and install 2 magnaflow mufflers with no tip, is a resonable price or is too much? and also if i change mufflers and go with performance i will decrease mpg ? thank you!

 

straight pipe just to the resonator or you going up to the cats?
*you better be going up to the cats

either way, I'm thinking the price is about average

 

pipes will be bigger size and will pass the resonator (will be eliminated ). changing pipes and mufflers will decrease or increase the mileage /gallon ? or just when i pass few k rpm will drink more gas...?