lm1's don't have mufflers, powerflos do.
my buddy used to have an o/r h and lm1's on his 07 gt, and it was INSANELY loud. sounded pretty much just like my car (i have an o/r h and lm1 catback exhaust, the only difference is lm1's come with resonators for 99-04 mustangs).
with powerflos you'll...