[aerohead]

I've been pulling everything I have together from actual tests done for interference drag.And the mirrors can't be discounted as they can effect a large area downstream.The good news for modern cars is that modern carmakers are the beneficiaries of all the aero research thats been done over the past decades.Streamlining,frontal area reduction,and moving the mirrors more outboard or away from regions of accelerated flow,have all helped to reduce their drag contribution.I'll keep compiling info although I don't know if I have any revelatory data.Will post it as I can.