[cosmo]

I bought a 1998 NB and the speedo is off a bit. i am running 205/55-16 on it which i am positive is the stock size. made sure the tire pressures are all at 35 psi. set the needle at 70 mph. and verified by tom tom and Garmin the car was only doing 67 mph. now when i had my 2005 mustang i used a diablosport predator to change the revolutions per mile thru the obdII. do they make a tool to do this for NB or not should i just get larger tires? does anyone else have this problem running stock size and being off by 2-3 mph?