IMO
It is best to purchase parts from a local dealer, IF you have access to one, especially IF they are reasonably priced.
Which would mean a few dollars more... yet this would give you the face to face option of rejecting an inferior part, without the added effort of RMO and all that #*#*.
A nearby dealer might have an employee that lives very near you and they might be willing to deliver the part to you.
(This was the case for a significant auto parts account I once managed.)
Some belts seem to be a slight bit different in size. The smaller of two will bring more top speed, the larger better acceleration, yet lower top end.
The racer's edge ? It's most likely a drive belt should be warmed up Before making that Urban Assault, to avoid possibility of those exploding belts we hear about. :-)
redk