Unless you want to invest ~$80 in an alternative direct drive rear wheel sprocket and hub mount do NOT go with a 3-speed internal shifter hub for a regular build. The motor drive sprocket won't fit over the hub, by a lot.
In short if you want to go direct drive and have better pedal go external gears as this was a nightmare.
I didn't say I couldn't pull it off, it just cost me an extra $30 and an entire day (10 hours) of 'no fun' work to make it go.
Just a tip on bike choice, avoid internal hubs if you don't budget an alt rear sprocket, but why? For ~$100 more than the sprocket mount you can Jackskshaft the thing.
The warnings I wanted to get across to you guys aside, I was happy to put my KC's Kruisers stickers on this new difficult build too because, well, I pulled it off pretty well I think ;-}