I spent a ton of time finding this. I am actually kind of ashamed of myself, but I bookmarked it and also saved the photo to my pc.
http://www.mazdas247.com/forum/showthread.php?123691754-505-Intake-Manifold-COMPLETED!&p=5644663&viewfull=1#post5644663
This picture shows a 33 whp and 32 wtq gain, which is absolutely phenomenal and totally worth $800, but dyno's are not very trustworthy. What's particularly odd about this picture is torque drops off like a brick at 5.5k rpms. If he let off the throttle it would completely disappear (I've done a few dyno runs of my own), so it appears the tuner let off the throttle just a bit or there was some other tuning malfunction. The question is why. And then if he did let off, he appeared to to do the same for the stock IM but about 200 rpm earlier, so it's hard to take this graph seriously. The only thing we can say for sure is the area under the curve is better on the 505.
The best gain seems to be around 4500, but then what is the difference between the blue and red line and why does the red line take a massive dip there? Too many variables, too many questions.
That definitely seems like serious gains, but I think most of these gains are from removing the butterflies and chamber walls of a stock intake and giving the throttle a straight path to the engine, when it needs to flow most.
After spending a very regretful amount of money on a dyno on my C6, and seeing drag strip results that did no correlate, I switched to drag strip only tuning. I simply don't trust dyno's. There are too many variables, too many liars, and not enough airflow to truly emulate a real world situation.
It looks like 505 has a nice product, and I've put a lot of thought and research into it, but I think I'll hold off on this.