You really only have to be concerned with three things max for performance on the 323:
Intake. ~$350CDN
Exhaust. ~$1000CDN
Chip. ~ $350CDN
Short of those there are not any major gains short of FI.
Don't be caught in the mentality that Dinan = God either.
Since you said it was a base model it's going to be high. H&R's won't drop it ALL that low. Coilovers are gonna cost you $$$ though.
Just remember even though it might be the base model it still handles VERY good compared to other cars. Even the 320i loaner I had, although slow it handled very well despite the body roll.