As mentioned, it is great to see some actuall testing being done, good work B-Man.
Here is a thought for anyone thinking of doing something different with a plenum. A while ago I saw a pic of a tuner in Japan that had cut the Rb20det runners off a couple of inches from the head and then had welded an RB26dett plenum on...I decided to do this so I took heaps of measurements and they virtually match up.....I bought some more runners and was about to buy the plenum but decided to sell the car.
So, these guys in Japan say that their plenum works very well and flows well also....this may be a good option for those wanting something a bit different, my only issue is that the runner length will be shortened dramatically so I dont' know what this will do to either the top or bottom end of the power ??