FWIW, I did the stock swap/replacement with the OEM tensioners, using an indie here in the Houston area. $350 and change is what it ran. 40k miles and one was pretty worn, the other still in good shape. The design still leaves me baffled...
To do the upgrade was roughly double that, and while I understand the improvement (which HD obviously doesn't), I also needed the extra $$$ at the time for other things. Some maintenance is obligatory, other stuff is on the wish list...