Yes, built like a POS -- as were almost all of the British sports cars. But picking on British Sports cars is like fishing in a fish tank. That's kind of the point though. From POS to automative works of art, I really can't think of an example of a higher powered low production variant that over time didn't hold up well on value. Simple formula that always seems to hold:

Attractive design + highly upgraded factory power - large production volumes = some collectability

American muscle cars all followed the same formula. They sell for silly money today compared to their low-power sister cars, even though most who had them before they were worth anything remembered them as having questionable reliability, so-so handling, and (as comes from the factory) not all that fast compared to modern cars.

The TR 7's and 8's like pretty much all were some nice designs seemingly engineered by the blind and built by the highly astigmatic. Same for the pre-emissions lot. Lotus Elite's, Bristol's, AC's. Sunbeam Alpines/Tigers, Jaguar E-types, Austins, MGs etc. All had the build quality of lego, and those who developed attachments to them did so in spite of it as all were more fun (on the rare occassions they were running) than their contemporaries. Forget the glamour names. Even in the low rent district, MGC's and Triumph GT6's and apparently even the TR8 sell for more now than they did when new.

There are higher expectations (and prices) now for cars than years ago, and the SRT-6 is objectively at least 10x the car that any of them were given all the technology, engineering and build quality improvement.