I have a 99 Civic EX and i love racing autocross. I want to know if getting used 99 Civic SI Springs (for stock shocks) for my car will increase handling? Used SI springs are a lot cheaper than performance springs.

 

you wont get any gain from it, the si springs are just a little heavier duty because the motor in a si weighs alot more than the ex, dont cheap out on suspension you get what you pay for, save up and buy little by little til you have everything.