I have a question about upgrading to a bigger tire and wheel combo on my 2003 Cavalier. I just got the 16" alloy wheels that were the premium wheel offered on the cav to upgrade from my 14" hubcaps with 195-70-14 tires. I know i know... i could have spent the money on the GN but i drive this car a lot more than the GN so i had to try and make it a little less wimpy looking. The question is how do i figure out how much this is throwing off my speedometer and how and where can i take it to have it recalibrated (cheaply) for this change. Thanks