Howdy all...
Last fall I bought a DevilsOwn water/methanol injection kit with plans to use it on my 84 300ZX. The engine already makes decent power (453/484) on 93 octane and 20PSI, but I was looking for a little more. The short story is I got busy with other things and it sat on a shelf for the last ~8 months. I finally got around to installing it late yesterday night and decided to post up some pictures and comments.
Here's the cars "mod list" if you are interested:
Modifications
Pump mounted to front upper cross-brace (don't worry all the lines are sip-tied into place now):

Progressive controller:

Line running under charge pipe up by TB:

Nozzle before TB, by blowoff valve:

Now, I usually only run 18PSI on the street (425-ish RWHP). I should note that I was a little skeptical as to the gains of water/meth before trying it out.
I used a 7gph nozzle, and the controller is currently set to start at when my very much maxed out ford cobra maf hits 3.8vdc and maxes at 4.9vdc. I would like to have it max out higher as the maf voltage is up to over 5.4vdc at 20PSI and I have a static voltage drop using resistors soldered into the maf circuit in my ECCS.
At first I was running cheap -20 (38% meth?) washer fluid, but now I've 50/50 mixed water/meth and had better results. I went from being able to run 10.80AFR and 26 degrees advance at 19PSI without the injection to 11.2AFR and an amazing 35 degrees of timing. I tried it out a little at the dragstrip with and without the injection while changing the tune accordingly. I seem to have gained about 2mph from the additional timing and leaner AFR's, going up from 118 to 120mph trap speeds. I'd call that a pretty good gain, and I also believe it's tuned much further from the detonation threshold than before.
I have yet to try straight methanol. But right now I am thinking it might be the best combination for this setup... I will have a lot more feedback and probably a lot more questions once I get it on the dyno with a ford lightning maf and start playing around. I would like it to eventually make 500whp on 93 octane, and I'll see how much closer the water/meth takes it to that goal.