Sorry, i dont quite understand the question. Are you asking which one is best to get, upper control arms, or lower control arms? If so, i think lower control arms would make the most difference. Good to have both though.
-GM
I would say some drag radials if your talking about the street and slicks for the track. I put on HPM Megabite Jr's which are lowers and it made a big difference. I also threw on a Spec clutch which just fried the tires because it engauges so hard so I think I'll have to do more myself.