I wanna buy either the skunk 2 lowering springs for my 99 cav but I am not sure what else i need to buy i mean is that it and have my mechanic swap the springs? Also I heard you need to get a new wheel allignment after lowering? Any of you guys with knowledge on this an input on what all i need to get for this.
 
with any lowering you need better shocks.struts to go with that.  the KYB AGX are good up to a 1.5 inch drop.  any further and the warrenty is void.
Koni yellows are good for 3 inches i think.
and you need a allignment after wards

Im a Xbox 360 fanboy...and damn proud of it!!
 
 
read the faqs on what you will need to lower