Hi Trev, thanks for the reply.
Appreciate that dropping the profile could potentially reduce ride comfort especially with our roads!!!!! however my previous two cars (none Audi's) had 45's or 35's and both were fine.
From a personal prospective I just don't like the look of the 50's and I'm hoping to improve the look with changing to the 45's, again just my personal choice.
Rolling diameter staying the same as is the width.
Todd..