Agreed with you there, CheapChump. I used the aluminum nozzle for one game and it was utter trash (fluctuations up to 100 fps). I also had issues with that set screw coming so loose that it made the nozzle seat far forward that I couldn't separate the upper and lower because the bolt was stuck into the buffer (that was fun).
I was able to find some very tense springs that are about the same diameter of the stock floating valve spring and a bit longer than the stock RA-tech nozzle spring. So I'm experimenting with those right now. The best luck I had so far was +/- 3 FPS on about 5 shots, but then I realized it was venting more gas than it was supposed to and the full mag was done after 10 shots... I'll report back if I find some better results.
I've been using my stock nozzle and it is still by far the best performer. With the stock nozzle I get +/- 5 FPS, so I would expect the RA-Tech to be just as good or better. Also as a side note, I was able to get just the stock nozzle head (as opposed to the entire nozzle) and ordered a whole bunch of em. Here's the link for those interested in that spare part:
http://www.evike.com/products/38475/