I just replaced my rear stocks shocks with KYB Gas-A-Just shocks. I chose the KG9090, which is listed for the Mach 1, because KYB informs me they are a bit more firm than the KG9023 they list for my model.

My question is, how important is the Quad (or axle damper) shock. I've had some Ford people tell me it has nothing to do with the handling, even though they are listed as a "Handling package upgrade".

I was going to replace it as well, but not sure if it's worth the time and money. On a budget.

 

The only thing that will get affected as far as the quad shocks go is wheel hop. It's pretty much useless IMHO. I've seen people remove them and adding some good control arms so they won't have wheel hop at launch..

 

If you get lower control arms or box and put stiffer bushings in your stock ones, then remove it. Otherwise, leave it since it helps w/ wheel hop.

 

I pull the damn things out as a matter of principle. Pull em out, get good LCA's like MM's, etc... and a MM panhard bar and you'll be lovin life. Just those two changes made it a totally different car for me.