I own an early CR car (serial number 73) that has a very thoroughly documented history - I have the original order form (purchased in 1996), and a copy of the ad from the first time the builder listed it for sale (in 2002), so mine had essentially 13 years of very light use on it when I bought it.
I spent
several days researching and reading everything I could before I pulled the trigger- I'm a very experienced automotive tech myself, but I didn't want any headaches, and I knew I was getting a car that has no easily available sources for replacement parts, etc.
Here are the summary bullet-points from my research:
1) I found NO major, or commonly discussed issues with the chassis or suspension mounting points; and my car has no stress cracks or weak spots anywhere on the chassis - It's a solid, well designed, and well fabricated chassis. It's not a mega high-tech racing chassis design (Mustang II front suspension with R&P steering, and live axle rear.); but it's more than adequate for a primarily road-driven car that might do a few track-days per year.
2) There are several (numerous) discussions out there about the CR's wiring harnesses, and the difficult wiring diagrams that accompany the assembly manual - My car seems to have had some past issues in this department, as well - several circuits on my car have been bypassed and re-run with heavier wire (most notably the fuel pump/sender, and the electric cooling fan) -
Mine also had an electrical gremlin in the engine electronics, but that was a Ford issue with the TFI ignition module moreso than a CR issue, so it doesn't count
3) The body is top-notch - It is as thick and rock-solid as an offshore boat hull. If you can live with the design deviations from the original Cobras (like the leading edge gap on the doors, and the fact that the car is larger than a genuine Cobra) then you won't be disappointed in the quality of the body construction
As others here have already mentioned- The rest is all about WHO assembled it, and how much they actually knew about getting an operational car all sorted out after all the "nuts and bolts" work is complete. My car had a number of lose bolts, and the alignment was way off (also due to loose tie-rods and loose adjusting nuts) so I needed to spend a few weekends going over it top to bottom.
Even if you aren't a "DIY" guy yourself; and have to rely on pros to service or repair your car, just look for a custom Street Rod specialty shop in your area - There are a ton of shops all over the US that have built custom Mustang II front-end Street Rods, who would look at a Classic Roadsters car and instantly recognize/understand everything about how it is setup, and how it should work. Don't let the lack of "official" Classic Roadsters business support be a major deterrent (JMHO)
Also- having access to the CR "gurus" here (most notably DV) should be a major benefit.
Regarding the assembly manual - I still have mine- It is a little worn and frayed around the edges, but I was considering having some copies ran at Kinkos, and offering them on Ebay, so if anyone has a CR car and needs a copy of the assembly guide, let me know via PM, and if there is enough interest I'll get some copies of it cranked out...