Good question and I've run the SR Lowering Springs
on my '01 with great results. I didn't have any caster camber plates at the time (I was young!) and I ate through tires, and fought my alignment regularly. If I could go back in time I would've picked up a set of caster camber plates and I think they should be mandatory when lowering any Mustang! I would recommend Maximum Motorsports Caster Camber plates
as well as there's many threads discussing their performance.
Something else to look into down the road in my opinion would be to pick up a set of Struts and Shocks
to complement the springs. No matter the age/mileage if you're going to do one, it's a great idea to do the other because you're either going to compromise comfort, performance, or both.
I hope this helps, Let me know if you don't have our discount code and shoot me a PM and we'll get you hooked up!