I would think that the 99+ SM's are running SM weight and taking out their RP's...keeping them legal for ITS. No allowances for those cars that would be illegal in ITS come to mind except ride height, but that applies to all three versions (1.6, 1.8 and 1.8 99+).

I can't think of anything for the 1.8's that would be illegal for ITA either except the mentioned de-powered steering rack for all years.

The 1.6 is a different issue. Conversion to the 94-05 diff assembly is legal in SM but not in IT as has been stated too, but they probably have the 4.3 gear in there per the SM rules, not that it matters.

Why types of issues are we seeing that are resulting in problems? As long as they are running IT weights, the cars are certainly not more potent.