If you don't care for sales persons, you are going to love me. I own the company. You can see what you want at
I70West Lightning Shopping!, Lightning Strikes in Online Shopping There is a sale going on and I think you are going to like what you see. These kits are a bit bigger than you stated in power.
Any kit can accept the 16AH 36v lithium battery in stock. That should give you the range and the power you need. I would suggest, for simplicity sake, you go with the WE 600 watt kit and order the 16AH 36 volt battery to go with it. I use the WE myself on my bikes. This comes with a thumb throttle. Takes about 20 minutes to install it from start to drive it off with a Hex wrench, adjustable wrench, tire tool and something to cut the wire ties that comes with it for the wiring. The only hardware it doesn't come with is the bolts to bolt the battery rack that's included. If you go with the LI battery, you will need two 12 gauge wire connectors from Radio Shack or from any hardware or Auto store.
Now, there is the Golden Motor system. But it's a bit more agressive in features and a bit harder to install. Not all hardware comes with it and it doesn't come with batteries.
Both are on sale right now for $349.95. The battery you need is also available but I don't remember the price on that.
I70West Lightning Shopping!, Lightning Strikes in Online Shopping