No offense, but the best way to get a sportier car is to buy one in the first place. For the price of an exhaust, intake, springs, shocks, plus all the necessary maintenance stuff you might need (you always need to make sure everything else is tip top before doing performance stuff; e.g. a new set of suspension bushings all around is always a good idea, wheel bearings, various suspension pieces that are likely worn out, etc), you could have had a *much* sportier car in the first place than what you'll end up with. Also, spending thousands on wheels/tires for a car like that is misplaced IMO. At the end of the day you still have a relatively heavy front-wheel drive car that runs a 16 second quartermile and doesn't exactly rip around corners; you can't change that with minor tweaks.
Seriously, if you want a sports car, buy a sports car - this is the most tried and true, tested advice I can give!!! Even a modest sportscar (e.g. an older Rx-7, MR-2, Miata, etc) will simply blow away a modest 'tuner' front-wheel drive car in pretty much every department, fun factor being the most important IMO.
Im my experience the absolute best way to approach cars is to start with something as close to what you want as possible, and change it the least that you need to (this also pays off for resale value, as most people look for near-stock cars).