And Jim there is something coming down the pipe that may change your tune, because in fact you can work with the exhaust on a 4 stroke to really change the way it delivers power. It is a different formula than a 2 stroke but still follows the same general principles. It has to do with optimal length and varying diameters in other words.
Definitely the drawback to 4 stroke is their width including a drive system as compared to an HT. If anyone had an extra half mil around you could probably solve the problem but in the mean time throw the q factor equations (http://www.recumbents.com/WISIL/qfactor/qfactor.htm) out the window and be gentle pedaling, if you ever do, with that left leg! I know plenty of folks that have bent bb spindles that only stuck out just far enough for the crank to fit on.
We are still testing. To be honest we have been busy doing some other work related items but will hit it again in earnest next week. I should be able to post some performance figures soon. I would say another 60 to 90 days before we have it on the market.