I was looking at a youtube video the other day for a a3 e85 tune from GIAC and they state it is completely stock vehicle. Now does that mean that there is undercover flex fuel engine that the a3 is running? If so please tell me which years and versions can run on e85 with just a tune without having to replace, fuel pump, fuel lines, sensors etc... I was looking at the s4 previously, but if I can run e85 in A3/S3 I won't even wait for the used car market to get better and get one now.