Ditto.
Tires first, then struts. A bit gray between whether springs or swaybars would be the next biggest bang.
At any rate, wheels/tires have a multi-order improvement potential. What do I mean? Well, better tires improve your grip, which will impact both the speed at which you can corner, and the effectiveness of your braking, which means you can drive farther into a corner before braking, and then allow the car to maintain a higher speed into the corner.
Lower profile tires will quicken turn-in and improve steering response.
Lighter wheels will improve handling via a reduction in unsprung mass, which allows your suspension to react more effectively to irregularities in the road surface. Acceleration is improved, also, since you've also reduced rotating mass.
Shop carefully for wheels. If you care about performance, ask about weight, and make looks a secondary consideration. (Might I suggest, Kosei K-1 Racing?...)
