Not sure if I will run this event with the truck (might do it in a car), but:
From reading the rules, I think this event is mostly likely intended for late model cars and bikes. If you believe you must have a rollcage to go 190 mph in a stock 2010 Corvette on flat asphalt with no trees or other cars, then it's not for you. That's OK. It doesn't make it evil, nor an event for daredevils only.
1 5/8" tube is permitted if it's NHRA cage spec (NHRA requires 1.75 for rollbar). And they state if you believe your rollover system is adequate, they will evaluate on a case-by-case basis.
No, it's not a replacement for SCTA events. Nor are SCTA events targeted for late model street cars.
Totally different animal. Short course, asphalt, aimed at street cars/bikes.