i really don't hear anything in the cab, i have the radio blastin, but its a nice tone, better if i remove the cats like they said, i dont have a video or anything but you tube is your best friend, heres 2 videos

http://www.youtube.com/watch?v=KekklYyThik
http://www.youtube.com/watch?v=vhkZbpuVB58

but for highway you might wanna keep loooking

 

Not true if you live in strict emissions states, like Colorado. I have longtube headers on my 99 f150 5.4, and got rid of the original 4 cats setup and replaced them with 2 magnaflow high flow cats. In PA I passed emissions, but I moved to CO and I failed emissions miserably. I failed both visual and emissions. My NOx was double what is allowed out here. The emissions inspector informed me that if the vehicle came with 4 cats, it MUST have 4 cats. What doesn't matter though is placement of cats, as long as 4 are on. So I bought 2 more magnaflow high flow cats and mounted them 4' in front of the muffler (magnaflow DI/DO muffler w/built in 'x' pipe), it was the only place I could mount them. I just wanted to warn people in advance before they have to spend more money

 

I would hope people know there emission laws before touching their cats. I live in Cali...I know allllllll about it.