just a poll.... which cat back system have you installed? I want to get one for my 2000 4x4 4.6 and would like some real world info rather than what the muffler shop says according to inventory. I put in a k&n filter only as well

 

40s Flowmaster

 

My F250 has a 40 series si/do setup with 4" tips and a K&N FIPK intake, & I love it! sounds great.

 

Borla 140136 SI/SO

 

Flowmaster 50 series SIDO with 2.5 inch rolled tips. Looks great, sounds great, can still sneak home at 3 am. Had the 40 on my last truck with maggie cat, gets old really quick.

 

x2

Put the borla on my 2003 also, just love the sound of the borla.

 

Nice soundclips!

that rumble was what I was lookin' for, why I went with the Borla.

 

I just installed the K&N FIPK on my 01 SuperCrew 4.6 and it sounds awesome! I've got a magnaflow cat-back coming in this saturday from the following site: http://www.hottexhaust.com/ I'd recommend them to anyone looking to buy a new exhaust. All my research from these forums as well as fordf150.net has pointed me towards this exhaust.