Yes the mod to the rf adapter works very well. I did this about a year ago and ive been using my wirless controller on my pc ever since and its just as good as having the official M$ adapter.
Also the diode is only needed to drop the 5v from the usb down to 3.3. What ive actually done for mine is found a good 3.3 point on my pc's motherboard and soldered a wire to that so i didnt have to worry about a diode and then mounted it inside of my pc case for neatness(if thats a word:p). Then i used one of the unused headers on my mobo for usb instead of using an actual usb port on the outside of the case, see what im saying??
I have been using it for awhile now and i love it. Also the best thing about it is it will let you connect up to four controllers at the same time just like it was in an xbox and it can even use the wireless guitars for guitar hero on the pc. They only have GH3 and GH Aerosmith for pc i beleive but its still pretty cool none the less. Just go for it and i promise you will NOT be dissapointed.