I've had the Bose Amp in my 3dr 2007 S3 fail due to the common rear washer pipe leak. (What a stupid design!) I have removed the Amp from the boot and now need to find a replacement. The part number for my failed Amp is 8P3035223A. Does anyone know if the 8P3035223B (for an A3 Sportback I believe) will work as a replacement or will I have to get hold of an "A". Thanks.