So I picked up a set of 18″ fronts and 19″ rears for my Gen1.. am going to be ordering a set of the Pirellis that are on sale for us,,, am wondering though has anyone done this and if so how much did it throw off the speedo? Did it affect the ECU? I plan on putting a set of 3:55’s this summer along with the ratio adapter but still the original difference seems to be about 10%…. is there a way to fix that ? Do you just live with it? OR is that something that needs to be done with the TUNE? thanks in advance.
