With all these sticker talk, I'm thinking there must be an opportunity here for the likes of Autoplus and Speedlab... that is, they can make available to the public marketing or promotional stickers that anyone can put to help the business gain visibility, but they should also have a line of "premium" or "performance" stickers that they will make available to vehicles that underwent tuning processes and passed certain criteria such as speed/power increase, etc.

That way, anyone putting on any of the regular stickers will be thought of as people trying to help promote the shops -- whether the cars themselves have been tuned or not. But those sporting the performance stickers will be known (at least among enthusiasts) has having passed certain tuning processes and criteria.

And personally, I really dislike seeing people virtually cover their cars with inappropriate stickers, such as a Town Ace that I once saw that sported Spoon, Nismo and Ralliart stickers side by side