This is the kit I have:
Subaru Robin Motor Gear Chain TRIKE Bike engine Bicycle - eBay (item 120507410680 end time Feb-14-10 17:22:09 PST)
Do yourself a favor and just buy their custom wheel. It's very good quality and was straight as an arrow.
It will pull all but the steepest hills here without pedaling at about 250 lbs. total weight. I live in the rockies where there's LOTS of hills.
I used Bing and Ebates cashback to get 14% back. The Bing has dropped now, with both of them it would be 10% cashback.
I LOVE my Staton. The kit was very easy to install and is very high quality. There's a lifetime warranty on the gearbox, though I doubt I'll ever need it. That little R/S engine is the little engine that could. For it's size it has an amazing amount of power.
I hate to say this since DAX's customer service has been nothing short of amazing but their Titan just doesn't ride like the Staton for me. No matter what I do I get bad grinding of the chain/sprockets. I've replaced the small sprockets and bought a Manic Mechanic sprocket adapter and sprocket, that helped a fair amount, but it still grinds and just doesn't compare to the ride of the Staton. The Staton is also the only true freewheel set up I know of without having to disengage anything, just let off the throttle and you're coasting.
If you're interested in a DAX I'd sell mine. It has quite a few extra parts too. Maybe you'd have better luck with it than I have.