Got it. B6 is street AK is track.
Clone, you saying no boxed arms and bushings? Need to put the rubber to the road and I thought this was the best way.
You have to remember that these cars were originally designed to be granny cars, not sports cars. There is only so much that can be done with bolt ons. Real high performance requires complete rengineering of the suspension in these cars which is why the GNX uses a completely different rear suspension from standard G bodies.
As for as simple things that can be done, a better choice for control arms would be aftermarket boxed arms that use roto joints which are a steel ball within a poly race. Even just new rubber bushings will perform better than 40 year old factory original rubber bushings. The stock rubber bushings operate like a crude ball joint in allowing multiple axis of rotation. Poly roto joints are a poly version of steel ball joints which allow several planes of rotation without deflection. Simple poly bushings behave like metal bushings in only allowing a single axis of rotation which isn't good for 4 link rear suspensions. Many aftermarket performance parts fod these cars are designed for track useage and not really intended for street operation.
So for the rear, just lower boxed rear arms with roto poly joints and stock upper arms with rubber bushings. You can also build a rear frame brace called a Jeff bar to help reduce rear frame flex.
http://jeffd.50megs.com/frame_brace_page.htm
There are also aftermarket rear shock mount and LCA mount braces available.