Lateral location of rear axle

[Skankin]

The GW lowers have the del-alum bushing that DOES do a decent job of lateral location (obviously there's some bind associated with it though).

Check out the 4 link for $400, or with a panhard and coil overs for $785
http://www.artmorrison.com/

This is a sensible product. Much more adjustability than the steeda kit, and less than half the price! I'd like a longer/beefier panhard though.

It's not mustang specific though, so it probably wouldn't be much more work to fabricate your own (at half that price).