Welcome! You're already a step ahead with the 5 speed, I wish my 03 ES was stick.
Suspension mods are the best thing for these cars, they only improve the already great-handling platform. A decent cupkit (Tokico blue shocks with Eibach, Tein, H&R, Tanabe, Racing Beat, etc springs) with a bigger rear swaybar is a great start.
A catback, header and short ram intake are all great for adding a little power too - can all be had for reasonably cheap on eBay (compared to other cars).
Also a heads up, since you're a fellow Midwesterner watch out for rust. It's easy to fix if you catch it early (a little sanding, body filler, primer/paint/clear goes a long way), but these things can quickly rust out pretty badly. People have all sorts of tricks for preventing rust, search around and you'll find all kinds of methods.
Drive it and have fun!