Are you asking what you would need to do to an otherwise-ITA car to be compliant to STL and run that weight? We have whittled away at World Challenge safety regs that would make an IT car non-compliant (e.g., fuel cell*, fire system, wheel stud thing, etc) but we were not able to remove the lateral dash cage bar. Put that lateral bar into your IT car and you should be good.

As far as car prep goes, just ensure your engine meets the valve lift and compression ratio specs (most do) as well as other spec limits (brakes, wheels, tires, etc).

With a lateral dash cage bar, most cars are areal STL compliant...

- GA

* Fuel tank needs to be in front of rear axle to be able to run without a fuel cell. That's a prob for some cars like the RX7.