Road racing suspension

[Spray-Bomb]

Hey guys, Im planning on building a full chassis for my truck Killer

The plan is road race driver that is powered by a twin turbo duramax

I want this thing to ride about 2 to 3 inches off the ground to the door (truck will be doored)

Most likely will be on 20" wheels & whatever tire sizes & have to run to make em work (will go smaller wheels if needed)

What my questions as of right now are: #1 would I be better off building the frame from round tubing or something like 2x3 rectangular tubing ???

And #2 I want to run IRS & an improved IFS, so what would yall suggest to run front & rear... Mustang II, C4, ??? in the front & C4, explorer, Jag, ??? in the rear

I want this thing to be safe & handle great, so hit me with what you got

Thanks, Matt