You mean the circular Mazdaspeed emblem that is on the ENGINE cover (no one puts stickers on valve covers)? I don't think there is anywhere to get it other than with the engine cover.
You can get the badge from the dealer seprately from the plastic engine cover. You will have to peel the remains of your old badge off and apply the new one. After that wait 10K miles and repeat the process. The plastic clearcoat on the badge can't handle the heat.
Both my engine cover badge, and the one on the rear have discolored. The lettering is supposed to be silver, but has changed to sort of gold. And the rest of the badge has a green tint to it.
The plastic coating on mine cracked after racing hard one night, and pretty much crumbled when i touched it.. the sticker itself is still in tact, except for cracks..
