Griggs and MM are pretty much comparable. (some people will argue that... <shrug>)
I had the MM coilovers on my 01 Cobra. I loved them. My ONLY complaint was that I got their kit with non-adjustable bilstein's rather than being patient and waiting for them to release their kit for the Koni D/A's.
That's not an issue for you as their fox stuff has been around for a long time.