Edit, since I'm too new here, I can't include links on my posts. If you add the http bit they should work.
What a great project!
I've always loved the efficiency of the original Insight and I still own a low mileage one with an original GM EV-1 motor installed. It has run sometimes but never well since it lacked a properly tuned AC controller. At this time it doesn't even have batteries in it. Clearly, I have too many projects!
I first ran it with welded axles similar to your project and then later got worried (though they didn't break) and spent the $500 (in 2009) for custom axles made out of 300M material from nitrodriveline. (In case someone wants the phone and address:
http://www.streetperformance.com/par...rivelines.html )
As a reference, you might like this power graph that a friend of mine made after we did tests on my gas insight with 800 extra lbs of ballast in it. We took it to about 95 mph and did coast down tests. This was back in 2003 or so, before he helped start Tesla and we were checking if it might be possible to drive coast to coast on one charge as a fun stunt.
He determined at the time that BC MX to BC Canada was probably possible on one charge, but not coast to coast due to the linear rolling resistance linked to the extra battery weight.
http://cafeelectric.com/insight/Insi...PowerGraph.pdf
It looks to me that yours should be lighter than our test weight and this shows about 150 wh/mile at 62 mph.
In case it helps, here are pictures from my initial conversion. The orange motor mounts were welded steel and they were attached to the insight structure with large metric rivet-nuts.
http://cafeelectric.com/insight/Conv...sightTemp.html
And page 2:
http://cafeelectric.com/insight/Conversion/Page1.html
I'm looking forward to watching your progress on this! If I didn't already have so much invested in the EV-1 motor I'd be tempted to do the same as you with the Leaf parts. But since I don't really have a special need for such an efficient EV, I expect someone else will take over this project before I get back around to it.