I have a ECSB 4x4 magnaflow mufflers it ran 16.20et. With modds it gone a little faster.

 

I should have a chat with my dad. He's been trying to convince my mom to let him mod their 8,1L but it still needs to be able to tow the horse trailer with ease. but everytime I drive my SS down to visit he gets the bug.

 

with mods in sig. expect for cam best I have is 15.42 @ 87.5mph unless torque management is removed their but-a@# slow. Also this all stock exhaust even the muffler.