Nice plane, and fun to fly, but I agree with the considerations of the wing spar. Further to this is the word that Avgas has a challenged future. Tomahawks are very unlikely to be approved on Mogas, their fuel systems will not tolerate the higher valpour pressures of Mogas (I've tried). Thus these planes will be dependant upon a suitable replacement fuel. I'd rather invest in a type for which plain old Mogas is a good alternative, so there are less concerns about getting fuel in the distant future.
As an alternative, do the math when you go to buy. If the intended use is such that you fly off the remaining airframe life, and calendar time, before they otherwise expire, and the plane has given you what you need, you're fine. Scrap the plane, sell the engine, prop, radios, and instruments, and scrap the airframe. Some planes just will not live forever, but their last days can give you some real value flying. Also, you're not so worried about insuring the airframe, if you're going to fly it to scrap anyway...
But, do the math!