In those automotive test with convt and hard top, were those test done with the windows down or up. That would make a big difference. It would make a difference if there was a test with the hard top with the windows up vs with the windows down. Also can you put a hard top on the JH. I am not sure about the GCR, but I thought that it had to be approved or listed that a removeable hardtop is allowed. I thought in IT that removeable tops were not allowed, with the exception that miatas can run the hardtop ( were it is listed on the spec page.) It is not listed for the JH or the TR8/7. I am considering building a 8 coupe, but I do not think that the convert. has a major disadvantage. I would say that my 8 convt does not loose any ground to the 8 coupe at the end of long straights, and even may pull alittle. I am not saying that coupes or sedan are not better, I just think in our applications and the fact that we have to run with the windows down and that the convt weigh less there can't be much of a major differeince