WS6 did not get posi or rear disk standard.
WS6 from 85-92 up, not sure about before that, was stiffer springs, 16x8 inch wheels, 245/50/16 tires, 36mm hollow front sway bar, not sure about the rear but it was big too. I think that's it, the IROC got the wonder bar to make up for it's smaller front sway bar, I think an IROC's suspension just depends on the IROC, WS6 has really stiff springs though.
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1989 Pontiac Firebird Formula LO3 Auto -180 degree stat -Hooker Cat-Back -velcro t-top bag -Wonder Bar from my IROC Waiting for install: Open element 14x3, 95 vette lt1 cam
*****Possible future mods*****
4th gen seats, fiberglass spoiler, rear disc, 3.42, torsen(posi), Edlebrock Performer TBI intake, headers, y-pipe and cat, afpr
1985 IROC-Z, TPI Auto
-Accel Super Coil
engine and tranny overhauls coming this summer http://www.geocities.com/krt80/
[This message has been edited by Keith5 (edited August 01, 2001).]