For my brothers 99 gt what do you guys prefer having magnaflow or slps? Which one would be louder?

 

Slps will be louder but bot sound as deep.

 

Out of those two options i would say slo, but be warned they get very loud and raspy at higher rpm's. I would much rather have bassanni or borla. Borla may be a bit on the pricey side but theyre the best in the business and quality is unmatched. There are plenty of vids on youtube. Check out my page "the808monsta" i got a couple vids