Joined: Jun 2014
Location: The Bluegrass State
The market fluctuates wildly on these cars. In summer '15 when I was shopping, nice 99+ GTs were $6K give or take a grand. Mach 1s were $10k give or take a grand. Right now, it seems like Machs have gone up, while GTs have gone down.
Since all of these cars are now too old to finance and guys are paying cash for them, the GT is always the best buy because you can use the difference in $$$ to buy mods and wipe the floor with a Mach 1 or Cobra. The Cobra Termi is the worst deal because you get stuck with IRS and less power than the new Coyote motor for $20,000. It's insane.
As far as pre-99 cars go, you should find them for $5,000 and less any day of the week.
2003 Mach 1 - TR3650 - Ford Performance aluminum shaft - Mac O/R H-pipe - Airbox modification - 17% tint
Gone but not forgotten:
2001 GT auto in Zinc Yellow-Flowmaster mufflers - Pypes O/R H pipe-Eibach Sportline springs/Koni STR.T shocks-AMR wheels w/ 315/35 MT Street Comps-FR 3.73s-Blankenship Performance tuning-Steeda Under-drive pulleys-BBK CAI-AcuFab 70mm TB