Backfire
 

I was wondering with the fast intentions catback exhaust with 18" resonators with long tube headers, that it'll backfire and pop when I let off the throttle

My set up which was and still is Fast Intentions test pipes, custom made catalytics in the exhaust use to do that and i loved it. It felt badass to me unfortunately going turbo took that away. Forgot the 18" resonators with carbon fiber mufflers

It could backfire with lth.

I have FI LTH and have tried both 12in and non resonated. Neither of them backfire, as they shouldn't N/A because A) we don't make that much power and B) because the car was tuned properly. Now you can have your tuner enrich your tune near red line to make it backfire. But honestly that's just retarded