(Note from admin: I split this aero question off from Tom's introductory thread, which is here: http://ecomodder.com/forum/showthrea...ota-23502.html )
Hi Tom -
Hope you don't mind I split your introductory post into two parts. More eyeballs in the aero sub-forum to address this question.
But I think the answer depends on the design of the topper. Is the exposed area flat with sharp edges (bad), or are the corners radiused?