well there is a speedo error for sure. i checked it using the speedometer in my android phone that uses gps sattelites to show the speed. when the speedo in the car shows 100, the gps device shows 92. but after upgrading to 16" alloys and 205/55 profile tyres, the error reduced to 96 when the speedo showed 100. you can check my top speed here http://www.youtube.com/watch?v=CQAF7335eYY&feature=player_detailpage. this was on blr-hyd highway. my car did a 190kmph in stock condition before i changed my rims.