The difference generally in aftermarket reeds are that they are Carbon Fiber, which allows them to be stiffer and less likely to chip but also being stiffer alows them to open/close faster than stock. Improves throttle response. Not much difference power wise, unless adding other mods with it i.e. Pipe, Reeds, airfilter(pretty standard) But a must for serious motor builders who want to get the most out of there motor.
And for Brand, I'd go for the V Force as I heard everywhere that there the best out there. But unless your buying the other mentioned mods dont waste your time and go with a more affordable version such as the Boyseen Power Reeds.
And generally you can get most things cheaper on Ebay, be it New or used. As for any internet sites I wouldnt be able to recommend any as I have strictly bought off of Ebay.
Hope this helps.
