Eh, hard to explain, it's been 20 years and I was in college. I'd say they didn't really have a shop, they were some guys trying to make a name for themselves to break into the saleen/steeda type of market. Lots of hype, mostly. They had one car that I can recall, their Slot Car. Used to bring it up to Texas A&M Sports Car Club events. We had TONS of foxbodies in the 90s due to there being lots of used Texas Dept. Public Safety highway patrol cars auctioned off. As a result, we had the fastest group of foxbody drivers in the country (many of whom have gone on to win jackets or set track lap records). Anyhow, I don't recall the Slot Car being any faster than a decent ESP car, certainly not a 3rd gen or Madarash. They had my buddy Todd Farris, CP champ, drive it and I think he told them, "Eh, it's a mustang. Needs more spring, bar, tire, and shocks."
They were some of the first to run 16x8s, lol at knowing now these are tiny wheels. They also claimed their input helped Ford design the SN95 suspension...um, not much changed there as far as I can tell.
Mathis is legit but there is some debate regarding antidive, etc. If you really want to study up, go search corner carvers for threads mentioning Mathis.