In my experience, a ~250whp miata will beat a LOT of cars, including the usual suspects like mustangs, camaros (watch out for the LS1 cars with cams and bolt-ons, though), STis, evos, stuff like that. It'll even have a good shot at a C5 vette. The problem is traction. Stock sized tires are not going to cut it, and neither are street tires. You'll need at least drag radials to beat even an N/A civic or 5.0 mustang from a dig.

my 225/50/15 v710's break loose easily too. i'm gonna be softening up the suspension. currently running the typical street rate ground controls 375/250. gonna move the 250's to the front and buy 170's for the rear. With the car 400 lbs lighter than stock I just don't need that much spring. need more compliance