You could always go with a set of Tien coilovers. Lot's of Supraguys use those and I have heard they have a large range of adjustment, from nice and soft to very firm + height adjustability. Don't ask me how much they are, go to www.suprastore.com, or www.mvpmotorsports.com and look for your self.
I have TRD suspension package on mine. I'm very happy with the performence but I don't like how front sits little bit lower then the rear. Is there a way to fix this?
Anyway, I'll like to try Tein or HKS coilover on my next Supra. By the way, I belive HKS coilover's on sale at MVP.