suspension upgrades?

wow! thanks for all the good info, I really like the hellwig sway bar kits they are reasonable and dont require the tabs, I think we will go that direction, funny you mentioned the book by Mike Martin, actually one popped up on a used site that was just about 75kms from my house and my other son just happened to be driving back from that direction yesterday and picked it up for $15.00 sounds like we got a score! I will read through it, as for rear springs they may be a bit flat but the car has air shocks, my son is 20 and your right about the difference in cars his daily ride is a neon r/t so big suspension difference, he knows the Duster cant be that good we just want to make it a little firmer, I think we will start with fresh suspension components and then a sway bay, thanks