Once you have the $500 Budget done you maybe want to consider to continue on that path of building your car at your taste, or sometimes you just have a bigger budget out of the gate and ask yourself what can I buy for 1000 dollars to upgrade my car. If you go with the second option I would recommend beginning with the parts in the $500 Budget and add the sway bar and suspension.
Rear Sway Bar (RSB)
An anti-roll bar (anti-sway bar, sway bar, stabilizer bar) is a part of many automobile suspensions that helps reduce the body roll of a vehicle during fast cornering or over road irregularities. It connects opposite (left/right) wheels together through short lever arms linked by a torsion spring. A sway bar increases the suspension’s roll stiffness—its resistance to roll in turns, independent of its spring rates in the vertical direction.
There are the companies that you can choose from:
– Autoexe
– Whiteline
Suspension (see the complete thread Here)
You can choose between spring / strut combo or a good set of coilovers.