Does TRIBE let you demo wheels?

I am torn between getting a new wheel set...i have been going back and forth between deep dish or climbing wheels such as the mavic kysrium (sp) that everyone raves about. My riding style...on a good day i can achieve and consistently hold 21-22, sometimes 23 if its a really good day. I am going into my 3rd year of cycling and would like to make an upgrade.

Does Tribe let you demo both deep dish as well as climbing wheels? I would like to feel the difference between the two before i purchase a pair.

If anyone has their 2 cents regarding my dilemma I would appreciate it. Additionally, my current wheel set is 1900 grams...many wheel sets i have been looking at are 1300-1400. Can a different of only 500-600 grams be enough to notice?

Thanks