[1.2gees]

I think undertired tires feel much better than over tired cars. You don't push the chasis as much when you have less grip, thus all the responses are crisper, cleaner. If you want a more "fun" drive, I'd go after things that make the suspension geometry change under load.

Shocks/bushings/springs(and torsion bars)/sway bars, in that order.
Ahmet