Look under the bonnet, if there's a big black bit of metal shaped like a tennis raquet you're in trouble. If that is there the first thing is to convert it to MPEFI.
Then 2.5" exhaust, intake mods (ie, XH snorkel, different air filter), extractors (jim mock, pacemaker), camshaft (wade 1004, jim mock), maybe swap to an ef/l intake manifold.
If its a 3 speed auto, ditch it. Grab a T5 manual. Or if its a 4 speed auto change diff to 3.45:1 or 3.7:1.
Perhaps an aftermarket computer to control all those mods ?
Or if you really want some OOmpf, talk to some of the guys on here who are turbocharging their cars.