What can I do to beef up my 91 chevy caprice

That is such low mileage- very rare in that condition- and kind of a cool car- just leave it factory stock and enjoy it the way it rolled off the assembly line 26 years ago- if you MUST, just do some simple things- exhaust headers, wheels and tires- don't do anything major like putting an LS1 engine in it, or anythin'

Exhaust (and headers), forced air induction or swap in a hyper-tech chip or just swap in a cold air intake from a Caddy (http://www.impalassforum.com/vBulletin/10-caprice/287089-92-caprice-classic-basic-cheap-proformance-mods.html). Personally I wouldn't touch it, just enjoy it as a cruiser. It will NEVER be a hotrod without some serious money intervention. One of the stigmas against Caprice Classics of this vintage is the fact that a ton of ratted out ones are (or at least were) discarded as old cop cars that people bought on the cheap and ratted out even further with cheap speed mods. Don't take a nice non-cop car, well-preserved and not abused one and give it the same cheap speed mods. Just my .02