IF you want to go IT racing, you first have to figure out what you want to do. You can't run the notch back in ITR as the 5.0 as far as I know didn't come with a trunk. If it did then you can run it in ITR.

If you run the notch in IT, you will have to cage rules as the cage requirments may be different.

things that he did that you would have to change back.

Battery back to stock location, remove steeda 5 link, and remove 8.8 and install 7.5.

Also I don't know what koni's you have but in IT you are restricted to two external adjustments.

If you are familiar with the 2.3L you can make power from it, and can be competitive at certain tracks, as the brakes, and the suspension are the limiting factors of the car. The good thing is that the specline for the car covers a wide range, and you have options like the 4 v.s 8 plug, carb v.s efi, 4 speed v.s 5 speed, etc.. I know at roebling road a ITB mustang set track record and won the race aobut a half year ago. It has since been reset by an old ITB celica (little less power, but 200lbs lighter), but it is proof, that at some tracks it can be made competitive.

You can run the car regionally in AS, the engine build rules are well defined in the AS section of the GCR detailing everything from part # required, to the exact valve seat angles.