Team shocks, graphite shock towers, RPM A-Arms and rear inner blocks, but most important of all... work on setups. Shock oil and spring combinations. Pick a tire that you have a tough time putting power down and tune your suspension to get the most grip. Then pick another set of tires and try them... you should see a huge improvement!!
I practice on a dry track, then tune for that, then ask for water or water it myself, tune for that. All the while... keeping notes in a small notebook.
That's the best way to stomp the competition!!
PS; aluminum looks nice... but won't bend back like the the RPM A-Arms.