Interesting. However, at 2590lbs, you're going to need quite a bit more than 185HP/165TQ at the wheels. Those numbers are maybe competitive ITS numbers, but not ITR. Get them up over 200 and you might have something.
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If you can get to 200WHP, you WILL have something. ITS RX-7's run 175/130 at 2680lbs. Even at your 'bolt-on' numbers, you have a potent package at 2590. Your challenge will be to get it to corner like the other cars in ITR. Your advantage will be weight.