Just a quick update in case you are still considering updating your Grand Prix. I posted earlier about upgrading the gearing on my Grand Prix. I also decided to fix up the paint job as much as possible, and as cheaply as possible. In my case, since I ride in the DC metro area, where a lot of bikes get ripped off, I deliberately wanted mine to look old and ratty, which made the paint job easy, so it would be less desireable to steal. I achieved my objective and it doesn't look worth the effort to steal. As to the bottom bracket, my bike shop was able to tap and replace the bottom bracket with a cheap shimano 113 model, which included tapping to 26 tpi for $40.