Welp...FWIW...grab an old CRX HF shell, 86 HF, drop a tiny turbo, and HF gears, sticky tires, small rims, and a 50 shot, and it might make it in the 12's...but the MR2 will be a little harder unless your dropping in a 20 valve 4age, and have an SC or turbo. Light is light, but the lighter the car, small the wheels, lighter tires, and minor upgrade's here and there...both would be competitive.. Stock 87 CRX did 17's, I got mine to 15 with blown rings and some minor engine work, I know the turbo I put on it years ago prolly dropped it in the 13's, with the cheap PG LSD...but it was still over weight...by the driver and tires..
Meh...if I ever get mine back together, I'll have better info to throw at ya.
Just keep posting since you know were not a fart can haven here....