I was researching the best electric bike kit to convert my old Schwinn and found a discount coupon code everyone can use for the Hill Topper conversion kit, by Clean Republic: lisaolson. (Follow the link and the discount should automatically load when you purchase a kit, but you can also type it in manually at checkout). I was astounded how easy it is to install compared to the others out there. And, the price was much better. I didn't want to have to fiddle with a ton of parts to assemble while paying the prices I saw for other kits. I also was impressed with Clean Republics reputation and devotion to their products and customers. Beat the rest hands down. I was able to get a discount coupon code (lisaolson) as well from the site linked to here. The SLA battery is a little heavy at 11 lbs, but its quiet and powerful enough for me. I don't have to remove it often, just when I recharge it.
http://discount-ebike-kit.weebly.com