Other Car Rental Programs/Partners (ie. Alamo, Enterprise, Sixt) - difference between quicksilver and alamo.com?

OK, stupid question I know.

But what is the difference between registering with alamo.com and registering for quicksilver? (Both are online but seems to be for different things).

I am not a frequent Alamo renter, but I have an upcoming reservation that I have already made. I would like to short-circuit the whole counter process so I want to enter my credit card info, waive the insurance, etc. and then link the registration to my reservation.

Do i want the quicksilver registration or the alamo.com registration? I'm guessing the former, but will either do? I don't have a corporate ID.

Quicksilver is Alamo's priority club. They have a separate manned counter in most larger cities. If you have upgrade coupons or some special request then you'll have to see a counter person. Otherwise, I believe you can now use the automated kiosks whether you are quicksilver or just apply for the web site registration thing.