can someone tell me?
 

right now i have a 2004 f150 fx4 and i have a S&B intake and true duals with X pipe. and i have the gryphon with the custom tunes for my truck but will it hurt anything if i delete the rear cats or cut everything off and put highflows on their.. in other words do i need to get different custom tunes if i do this..

My rather uneducated guess is, as long as you keep the X-pipe, you won't need to change the tune. But, 88Racing knows this stuff much better than me, so hopefully, he'll get in here soon.

Why do you want to change what you've got? I really doubt it's gong to be worth the money.

- Jack

Nope.
No changes required.
Just make sure to get the o2 sensers back in the right locations.

ok thanks guys.. i just want to cut the rear cats off or just put high flows on to have a little more sound thats all.. i just didnt want to start doin this stuff and find out it would screw the gryphon all up..

If you have the 4 cat system now and want to put in the HF cats the cut all cats out and replace with the 2 HF cats. 1 per side.