a few questions for you experts out there

what are some options to make my b230F engine faster?

i recently got turbo sway bars from IPD for it, and i love them, my questions here is, would getting stiffer springs be worth the money? and how much more performance would i get out of them? i know i want the lower, sportier look, but performance-wise, what are the benefits?

ok, third and final question (for now): if i get a full headlight assembly from an older volvo with the 4 headlights (two on a side), is it possible to replace my 2 big headlights, and how hard would it be to do the converson?

thanks for any and all help :)

oh oh, i thought of one more: what are some options for reducing weight that wouldnt be easily noticed? i dont wanna fuck up the interior, but a lighter car = better performance (usualy)