There is a Dellorto/A3 intake that came on some of the later model A3's, and you can get one from Ike's Bikes. But it doesn't get the carb out from under the frame, and if the 15.15 is any bigger on the outside dimensions than the 14.12, I don't think it would fit even if you did have the intake. (Even if they're the same size, I still think it's a chore to get the 14.12 to fit).