Surely the point of a sticker is to show your a member of a certain group, and the point of this is to all be the same colour and design, or how do you know the difference when you pass someone going the opposite direction if that was a T6 Forum sticker, or just a tax disc holder, or dealer sticker.
My opinion is the Orange is nice and obvious, and follows the rest of the site branding.
I'd also be happy to pre-pay for one before you order, and as a preference i'd like it inside the glass.