I am not sure if Zen vision will be willing to serve you. They are more in charge of warranty and repairs.
I will also let Joey know she has many fans out there... She just dyed her hair purple and brown, did you see???
I think if you wanna touch and feel oakleys without much probing, try paris miki on taka (5th storey i think)
another good shop is on the 3rd storey of taka as well.... good collection of shades there.
as far as i know, oakleys' prices are pretty fixed. if you do get a discount, do make sure their warranty is valid within singapore. you wouldn't want to get them from a banned shop and find out your warranty isn't valid. Alomost happened to me once when I got a pair of twentys from serangoon plaza at 30 percent off last time