NDBoost - The "discounts" you mentioned have been though of over and over. The problem is in the fact that the various "Supra" shops don't support this community that much. Sure, they all say they offer discounts to Supra guys but at the end of the day all they care about is getting the sale.
Let's say for a minute that there is a national Supra Owner Group that has members that pay an annual membership fee. That fee entitles those members to preferred pricing at various shops (preferred shops also pay an annual fee to the organization to be a preferred shop). Shop X promotes a $5 widget with a 20% off for members in good standing with the group. Shop Y will just come in and offer the same widget for $3.74 (actually beating the preferred vendor pricing). This just causes the "membership" fee to be worthless.
I would love nothing more than to see an actual "organization" for the Supra owners - not just a bunch of loose communities that don't play well together. A community with by-laws, elected leaders, a charter, etc.
Oh well... I can dream can't I?