The power window controls are much different between Celicas and Supras. I assume by undercover the panel that goes by the gas pedals? If so it doesn't exist on Celicas. Pretty much the entire interior trim is different between Celicas and Supra. Front seats are the same the rears are upholstered different (at least in cloth). Most of the other stuff is different in it own little way. Most of the handles, some of the trunk trim, headliner, and a few other parts are the same though.