OK, Chris. Lets look at the math:
ITS Miata will make 163 at the wheels. The math puts that at 2430. Add the RWD factor and you're at 2490. Well, really you'll be at 2550 once the new RWD factor goes into effect. (assuming it's 5%, not the 7% I read about here. I like 5, easy math. , plus it's a pretty reasonable value all things considered. I think 2.55 is low.)
So, the Presumed and obvious main frontrunner is the Teg at 2430.
2430/190 = 12.78
2550/163 = 15.64

So, I'm not sure I'd spend money doing that, myself.
Now, Jim Drago thinks he can get a 99 motor to 190.* If so, that means
2550/190 = 13.42
THAT is worth a shot, and would be a good race.
Dunno about his number though, but I give him the nod when it comes to Miata motors.
*From a RR/AX thread.