Glad you enjoyed it!

BP51s are actually available in heavy and standard load options, with tons of spring rates available for constant load, so they are killer even on the heaviest of rigs. The Bilsteins can be set up for more weight that most with the right springs, but it is hard to beat the BP51 as they were designed for heavier overland type builds. The Bilsteins, although great under a load, are really more of a "prerunner shock" rather than an "overlander shock"

BP51

Sean, the owner the company, has these installed on his 2005 Toyota Tacoma. He loves them as they give the best tunability for more like daily driver/overlander.

Seems bilstein have more quality hardware

Not quite sure but we know they are all still doing R&D.

That is correct

I think you might be mistaking the bias for the fact that the 8100s are flat-out a higher-performing shock than the BP51, but that is to be expected given their designs. Neither is without their flaws, but the Bilsteins are definitely easier to adjust as well, especially since they are switching most of their 8100s to use quick-adjust knobs on the bypass tubes. With that said, it is all about the right shock for the right person. If you like to keep all four tires on the ground as much as possible, then you do not need the additional support of the Bilstein and could save some money and get just as cushy of a ride out of the BP51.

on the IFS platforms, that's correct, no rebound adjustment on the front coilovers