Glad to hear someone is stepping up to race an XR again. To answer your question at this point with the T5 your are in the SM class, the cool thing is all the mods you have listed would be legal in the SM class accept "maybe" the RS500 whale tail but it's one of those things until your in the top of your Class locally and Nationally I wouldn't worry about it, I you can help yourself try to spend your money on car parts the will make your car go fast and stay legal.
I ran my XR in the DSP class and won the 2009 National Championship, and then ran SM and had a lot of fun because of all the car mods I could do. Let me know if need more info and lets talk.
Ben 1985 XR4ti DSP, SM Class