I am in the process of purchasing a 1997 Grand Cherokee Limited. I have a few issues that I would like some help with. 1: The "spare" tire is a size P225/70R16. The jeep is coming with 20" wheels with P275/55R20 tires. What gears will I need to change over to to keep the speedometer correct? A interweb site calculated the speedo should be off by 7 mph ( speedo says 55 when doing 62). 2: Any one know where I can locate the seat leather? The leather stitching has come apart but also some has torn. I would like to replace the torn leather and restitch the leather in the near future. Any help? Thanks