Hmmm, good point Ian. I don't want to over-do it and have fouling problems. I'll ask Ed if we can perhaps experiment for the optimum. Re. the offset comparison, I just wondered if the 19" Y wheel had the same offset as the S5 standard rim - couldn't find any truly representative pics but for some reason had in mind that with the Ys fitted, A5s seemed to have their rear arches better filled than the S5.although if APS carry stock, you could try different sizes!