Info I have found on the Perrin WI setup (make sure to check out the "Features" and "Included" tabs also on this page):
Okay, so comparing pictures:
This setup appears to have the DDS3 flow sensor. The product literature says that it compares the actual flow rate from the flow sensor with the calculated flow rate. If there is a problem, it throws up a red flag. Compare the pictures from Perrin's website to the install pictures of an EVO guys Aquamist 2d/DDS3. Same sensor! This probably means that a DDS3 gauge upgrade for this unit would be cheaper by about $100 or so (because you won't need the extra flow sensor hopefully!). Although with the included controller doing flow comparisons and the remote control feedback from the Perrin setup the DDS3 gauge will really just be a toy and not a necessity like it is with the current systems.
Also, this setup comes with the much-anticipated bracket that Richard has been posting pictures of. It also comes with a fluid level switch for the supply tank. Those are both a huge bonus. The Perrin website also states that the pump comes with Teflon seals, but I think Richard has said in the past that the most recent systems already have the Teflon seals.
From the best I can tell, it has the traditional AquaMist 2d Pump + High-Speed Valve setup. The output of the AquaMist pump looks like it is connected to the input of the water pressure switch (the pressure switch appears to have a purple rubber cap over the top of it), and then the output of the pressure switch goes to the input of the DDS3-style flow sensor. The output of the flow sensor would then connect to the HSV which would then output to the injection nozzle itself. The odd part though is that I can't identify the HSV in the Perrin picture of the whole setup? Bueller?
The Perrin controller has pots for setting "when the injection starts, pump gain, and a trim pot for setting up the nozzles flow rate.".
We can assume that "When the injection starts" means either that the controller only starts based on the Injector Duty Cycle, or that it starts based on an included MAP sensor.
This is still a mystery to me right now. I would think that having it only start based on IDC would make the system a real pain to tune for (never would know exactly when it is going to start spraying?) I would assume that the system has a pressure switch like all of the others in order to kick the system on based on a certain boost pressure. "This main harness is used to connect the system to the vehicles battery, and other sensors." Perhaps this is where the system hooks into a MAP sensor of some sort?
The "pump gain" and "trim pot for nozzle flow rate" are also a mystery. I assume that the trim pot for nozzle flow rate means that you set it so that the feedback from the flow meter matches the expected output when the system is operating normally. Then the controller can tell when the flow feedback doesn't match the calculated output. Pump gain is a real mystery - maybe this is the pressure setting for the pump (3 bar, 5 bar, 7 bar, etc?)
It looks like all a person really needs to go along with this kit is a relay to drop the power to the wastegate solenoid for boost protection and a reservoir to install the level sensor and supply fittings into. I think a 50/50 mix of meth/water in the stock tank with the WI system drawing from there would be great dual-purpose setup in most cars. You can leave the stock pump hooked up to throw fluid on the windscreen so you don't lose that functionality.
SO, in conclusion:
The only two questions I *really* need answered is if the Perrin system does in fact use a High-Speed Valve setup like the Aquamist 2d system and if it is activated based on a boost pressure sensor. I would though also like to see the user's manual for this system. If anyone gets ahold of a copy of the user's manual, PLEASE post it in this thread!!!