Replace the RSX rear derailer with the newest and best thing you can get your hands on for a decent price (a couple year old Ultegra RD should do). If you can do that cheap enough, replace the crankset as well, or better yet, just put a flashy new outer ring (such as this: Bontrager ring) on it to get rid of that cheap, early '90s RSX/105 chainring look.

Otherwise, leave it as is - it'll appeal to the road crowd. Just try to get the emphasis off that RSX group.

-Kurt