'74S is the best of the narrow midyears. Better rear end ratio, no crappy airpumps and thermal reactors. Narrow rear bumper pads.. Potential lighter as well depending on options (is it a sunroof coupe?). I *thought* S's came with Fuchs, although the cookies are period correct, as no doubt the BROWN color is
The real problem is that there aren't many (any?) comparables out there. Most midyears are used up.. or have converted engines. Very few are still original condition.
I would check the underside for rust (the '74s weren't galvanized yet) in the suspension pan and battery box area.
I have seen SOME midyears "ask" a price in the upper teens to low 20s, but don't know if those sold at those prices. I would think if solid and engine is good (i'm thinking 35+ year old rubber fuel lines, vacumn lines etc should be replaced).. is a $10-15K car
* did a '74 have a 5 digit or 6 digit odometer? could it be 123K miles?
I'd also wonder why it was parked. Our 74S blew airboxes constantly when new (before the pop-of valve was "created") ... and blew a motor at 30K miles (admittedly mostly track miles).