I bought the Snow Performance "stage 3" kit. It includes a controller than looks at boost and injector duty cycle and allows progressive injection based on either / both. It includes an in-cabin controller with LCD screen / buttons. I did look at the CoolingMist system too.
I will be running 50/50 water/methanol. I have got a 2.5 gallon tank which should last for months of street use, and should be sufficient for many laps on the track (but you can really chew through it on the track).
I'm going to buy the "SafeInjection" module too which monitors flow and detects lack of flow (blockage) or too much flow (leak). It has an output which I will use to trigger my ECU into a safe and conservative map.
I haven't installed it yet as part of my ongoing R34 build, but will be doing so in the new few weeks. I am running a GTX3071R so I am hoping to run some very high boost through it to get the most out of it, as Mick_o did
Cheers
Justin