I got my ebike parts from him (well most of it anyway).
I originally got the side mounted kit. After my experience with that one...stay away from the side mounted kits. They are probably the worst design of the 3 basic kit designs he offers. It's mainly the mounting bracket is too soft and will bend under torque due to the way it's mounted. It also has major alignment problems with just about any bike I can think of putting it on and the two bikes I do have didn't work with this bracket well enough to be reliable.
So I ended up "upgrading" to a mid-mounted kit by buying the mid mounted bracket parts and freewheel motor cog from GNG. Since the motors he uses are are just about all the same in terms of screw positioning and gearbox size, I didn't have to replace the motor. (though he now has a 36v 450 watt motor that appears different in appearance then the others, so I don't know if that one can be used in the particular mid mounted bracket I have, I guess I would have to contact him about it if I decide to upgrade my kit again)
Here is some pictures of my current ebike. The crank set (pedal cranks, crank axle and chain wheel with freewheel function) I got from http://www.sickbikeparts.com
That site deals only with gas powered bicycles, but they sell the special freewheel crank sets separately and I saved a ton of money by getting it from them instead of GNG. Not saying there is anything wrong with the quality of GNG's cranksets or his pricing. But since I live in the USA, shipping from him will be expensive.
(click to enlarge)
You WILL need Bottom Bracket spacer rings to make the chain wheel line up with the motor cog. Just about any bike I've ever seen has the rear works being wider at the base then the bottom bracket itself, thus the spacer rings need to be used to keep the bracket lined up in parallel.
Close up of image of what I'm talking about: (this was taken when my kit was on my older road bike)http://memberfiles.freewebs.com/91/50/8 ... AG0024.jpg
The space in between the bracket and the bottom bracket is where you see the spacer rings. They keep the whole thing lined up. On my new bike the alignment is slightly worse and I'll need to add a couple more spacers to it so it will last longer in the long run. Before I can though, I need to find a longer left bottom bracket cup (that part the screws on and has a lockring). It's not quite long enough and it looks like if I add more spacers to the right BB cup, the left won't have enough threading left to hold the lock ring in place. So if anyone knows where to find one that's longer (Perhaps only 4 to 8mm longer is all I need) please let me know! I'm pretty sure the bottom bracket it self has enough threading to accommodate the cup since with it fully screwed in, I saw nearly a 3rd of an inch of spare threading by my rough estimates.
The battery I use now is a 36v 12ah LifePo4 which I got for around $300 after paying for the express shipping. I got it from eBay, so not all eBay batteries are duds. Just make sure to check the feed back and read the description so that you know what you are getting. I avoided the "duct tape" batteries. The one I got has this textured covering over it instead of duct tape. This was the seller I got the battery from:http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0773366163
Probably doesn't have real A123 cells in it, but it works fine for me nonetheless. I can get about 13 miles out of it (but I stop and charge it after 10 miles to ensure the battery isn't drained too much too often) on a single charge on motor power alone. I used to have SLA batteries with same AH rating as these and those only got about 5-6 miles before I had to charge them. That and the voltage sag on SLAs is terrible. Now that I've been using Lithium, I will NEVER go back to using SLAs.
If you are using a 450w kit, I would recommend getting a 15ah or higher battery. If you decide to let him ship it via sea mail, it will take 8+ weeks for it to arrive, but that could mean saving a lot of money on shipping. Otherwise it will be another $87 for express shipping on top of the $66 shipping you already paid when paying for it through eBay. But he does seem to price the batteries in such a way that it's still a good deal anyway.
I've gone over 120 miles in total on these batteries and they still have the same capacity and discharge characteristics they had when I first installed it, so I can now safely say the batteries this guy makes are reliable and won't fall apart like some duct tape batteries that other sellers have. (so long as you know what your doing choosing a battery box for it.
I recently uploaded a video of my current system. The speedometer is in MPH by the way.
The motor bracket does look thin, but it seems that it's not moving or bending like the side mounted ones did, and what bend that is present is from the ubolt and alignment issues from the bottom bracket spacing which will be solved when I get more spacer rings. The bottom bracket has seen around 200 to 300 miles on it thus far (my ebike is my only method of transportation, so I use it A LOT), and it has held up nicely.
Also, that sorta "hopping" sound the motor makes when it gets to full RPM is probably the result of the motor hitting the current limit of the speed controller. I may get a 450watt speed controller so I can get a tiny bit more push out of the motor and get rid of that somewhat annoying hopping it does on high RPM/load.