Comp engineering makes a good kit that will "fit" in a fox body. I always end up tweaking them to get them to fit nicer, but they'll work good right outta the box.
NHRA/IHRA are pretty strict as far as cage regualtions go. Not sure how the corner carver guys are though. Maybe get a rulebook from each sanction you want to play with, and figure out a happy medium. I'm gonna guess if you build one to NHRA/IHRA specs, you'll be good to go on the circuit as well.
