All-around, 4WD is more versatile, but racers usually go 2WD to save weight unless they suspect the course will need 4WD(Jeepspeeds are built convertible)
2-dr/4-dr,... The eternal argument. The stock 4-dr chassis is a little stiffer, and for an all-around rig, the back doors make it easier to get into the back. The 2-drs have better sheet metal arrangement for cutting out wheel openings.
They build and race both.
Personal opinion: With a fire suite, helmet, gloves etc. and crawling around a cage, the front doors are a little tight when you go to get in/out in a hurry.