Suspension kit

I was wondering what is the individual functions are of sway bars, springs and shocks and how each one increases your performance on the road. I was also wanting to know if progress, TRD, or eibach lowering springs would be best for my Pontiac Vibe.:p

Tein H tech or S tech springs are the best, S tech being a lower drop. also popular vibe springs are the Hotchkiss springs.