Does anyone know the standard rack ratio for the AJLs ? There seem to be two part numbers for AJLs. One is common to all N/A & Tdi V6s, the other is AGB (2.7T) & AJL only. Are these interchangeable? Is the S4 ratio faster? Can S4 and in-turn... us AJL guys upgrade to RS4 racks if they're any faster?