It is easy to do(relatively speaking, swapping and LED) but with the same driver you'll get a bit more output and a much floodier beam.
If you are planning to swap the LED and the driver, it might be cheaper to buy one of these
blank drop-ins and then install everything to it.
This drop-in is also similar to the eBay one and is much cheaper. Those might not use a real R2. R2s seem to be hard to come by.
Make sure to keep the current down so the LED doesn't overheat.
Kaidomain used to be better. Shipping is still pretty slow and now CS went down too. DX is better from what I hear.