I think Tom calling these Stinsons that are less than $40K projects is wrong and not looking out for the buyer's best interest. I think he saw the data on three planes I provided and just doesn't want to admit he's wrong. I'm not an expert on Stinsons, but if I see three of any given airplane type that all look to have good paint, good interiors, low-time engines, and they're all prices similarly... I'm going to assume that's a good market value for the planes. That doesn't mean you buy it without doing your research.
And a good prebuy. A VERY thorough prebuy. There have been way too many buyers stung when they bought an airplane that had good paint and interiors and low-time engines. That's what way too many look at, and forget that the airframe is the same age as a 1949 Ford or whatever. There have been many owners spend lots of money replacing the engine and making the airplane look good, but the serious stuff--the stuff that holds your soft pink body thousands of feet up--hasn't been closely inspected and the cracks and corrosion repaired. That applies to tube or aluminum. And the control systems! My goodness, you should see what I've found sometimes. Worn-out cables, seized pulleys, cracked brackets, bellcrank bearings shot, missing cable safety pins. No different, really, than the old car that gets paint and upholstery and an engine rebuild, but the steering hardware is all shot and the frame is rusted out and the brake lines are ready to burst.
Tube airframes can rust out from the outside or the inside. Putting pressure on likely places with an awl can identify bad spots. Just because the outside looks good means nothing. In fact, there are ADs on several manufacturer's wing struts for exactly that reason. Maule, Piper, Taylorcraft and others have such ADs. Imagine what happens if a rotten lift strut breaks in flight.
Citabrias and Champs can have broken tailposts due to tailwheel shimmy. The low-wing Bellancas experience cracking of the stabilizer forward spar mounting. 172s crack their forward stab spars and the bottom ends of the aft doorposts. 180s and 185s crack the lower end of their aft fin spars, and their stabilizer trim jacks are often decades past any recommended overhaul interval. You'll find them corroded and their dust/water boots rotted off. They're hard to see and hard to get at, so they're ignored.
Any airplane model has its weak spots, and a mechanic familiar with the model should do the prebuy. And the prospective buyer should be prepared to pay appropriately.