There are different thickness sway bars used on each model of Stagea and widths depending on subframes.
From memory, the auto's have a 19mm solid front and 22mm hollow rear, the manual S2 stagea's have 22mm front and 24mm rear. The auto stageas (by and large) run GTS-t running gear, the manual stageas use R33GTR running gear.
You are going to have to double check everything since it is a long time since a few of us played around with them and my memory might be a bit sketchy.