4 cylinder Fieros are in D Prepared. From Appendix A-----
"Pontiac
Fiero (4 cylinder, 2.5 L)
Alternate parts: Air cleaner may protrude through engine hatch; double A-arm rear suspension"
Minimum weight is based on engine displacement, for a 2.5L engine it would be 0.95 x actual displacement.
The 6 cylinder cars are in F Prepared. You might check out the Prepared rules, they are online at the SCCA web site. I'm not familiar with IT rules, but check and make sure that the car is legal in Solo.
And welcome to DP
Steve Hudson
DP Miata