Powerflex Black Series are a new offering from Powerflex. It's basically their same quality and fit, but in a harder compound polyurethane. Ideal for dedicated race, track and drift cars where you want it stiffer and you're not worried about it being harsher.
------ Powerflex have the following notes and info for this fitment -----
The Front Lower Diff Mount has 2 possible sizes 62mm use PFF44-107 and 70.5mm use PFF44-108
R` on the end of the part numbers for the mounts are for road use, for competition use the standard, non R, part number.
PFF44-105(R) is used twice on the vehicle. It is used for the Upper Engine Mount as well as the Upper Gearbox Mount