i put 18s on my s2000 and i got stopped because i was going to fast and my mph was saying 60mph. i was told i could tune my ecu to compensate. Any ideas?

 

18's have nothing to do with it. If your speedometer is that far off then you have a tire diameter problem. Run the proper tire diameter = problem solved.

 

http://www.ricks2k.com/products/yb.php

Speedo calibrator

 

This. What tire sizes are you running? The speedo calibrator is if you have gears installed.

 

Sounds like you're running a tire that is too large in diameter - which is going to throw off your speedometer AND give your car taller gearing (which will make it slower).

The right thing to do would be to ditch the ill-fitting tires, but if that isn't an option, then the yellow box calibrator linked above will work.

 

thanks you for the suggestions