dual exhaust on BD f150 help!

Ok guys i have a 98 f150 single cab...its traditional BD 3 inches and half way into my SFBD another 2 inches to the door...im no expert on motors or exhaust work. I was wondering do i need to have an X pipe in order to run true duals? or straight off of each cat on both sides straight back to mufflers? The way my tranny member being built the cats are goin to sit on top of it and dont want to run an X pipe if i can...will this effect my ECU or back pressure? thanks!

x pipe is a preformance option, it is not nessacery

i run straight back off each cat. don't have any problems and no check engine codes related to exhaust for 4+ years. aren't x-pipes illegal? or is just the "off-road" x pipe?

I'd run at least an H pipe under it

thats what i wanted to do...run straight back off each cat...no X-pipe or H, thanks!