Welcome to an addiction.

I would definitley trade up to at least 15" rims if not 16s the reason being is you get a better contact patch 17s are great but 18s are too much really.

I would look into a good set of coilovers but if not the H&R springs are a high recommendation (I run em and I am a corner junkie). Struts are a definite must and are the one major spot you shouldn't go cheap. They can make or break the handling of your ride in many ways.

Good luck