Easy choice of vehicle is a benefit of Emerald Aisle locations - long a point of differentiation from Avis and Hertz, although that difference has diminished in recent years.

There is some further price segmentation within Premium, PXAR vs. PCAR. Others have reported the 300C as a PXAR. EE status ought to overcome that point of resistance, IMHO.

At Emerald Reserve locations I am not at all reluctant to scope the lot and ask for something specific from the reserved car class (or lower). Generally that is met with quick agreement, but not always. I haven't experienced the drawn-out refusals as the OP describes but I don't usually give the location a second chance to disappoint: I'll rent from a different firm or location next time, and suggest that's what the OP should be doing.