Parts for a "new clutch" will be around $300-500 (OR MORE depending on the clutch), plus at minimum resurfacing of the flywheel for $75-100 at the machine shop. That's no labor on the actual clutch install. So $400 to $600 before the labor kicks in. A new clutch+labor should be budgeted for roughly $800. Hopefully less.
Now a new trans on a 10k mile car that was driven by some old guy that grinds gears constantly or who rests his arm on the shifter non-stop is another grand for a rebuild.
Then the rear diff that's shot from doing half-assed burnouts. There goes another $300 in parts or more with fluid plus labor. Lets call it $500.
New tires, not some used rubber from the junkyard or 1960's tech tires, but good tires, mounting and balancing at a shop that doesn't scratch the wheel and who can deal with knockoffs properly, there goes another $1200.
Replace various bushings and suspension components as needed, $500 with labor.
THe
oil pan is leaking after 10k miles. New gasket +
oil change at $250.
Carb needs a thorough rebuild and tuning after putting crap ethanol fuel in it. Another $300. Just tuning for better driveability will get you close to that $300 number.
Brake job, just the pads, we will spare the rotors this time, $250.
An annoying squeak that needs to be tracked down, $50. It was an easy fix.
Why is the fuel gauge not working? Well, there goes another $250 with the sending unit replacement.
All of the above can and should at least be CONSIDERED and BUDGETED for at 10,000 miles on these cars. Sorry, that's the truth. Search the Superformance, Backdraft, hell, any forum and look at the problems that creep up.
It's great that you could never possibly see putting $5,000 in to one of these cars upon purchasing, but you are avoiding reality for what many owners will face when purchasing a relatively high(er) mileage Cobra/kit/replica/classic/etc. Labor will obviously vary upon region/area. The $5,000 I suggested earlier was just a real rough number, but hopefully you at least realize why that number isn't all that far out there.