I've never tuned anything that has run both of these together. I'm approaching 10,000 miles on ethanol fuel (9700 right now ;)). Things are going fine, but it will need new head gaskets before too long. I have a set of new 440cc WRX injectors to install and modded fuel rails. I'll be doing the parallel fuel rail mod to avoid leaning out cylinder 3 too far.

I haven't really decided between the ZEX kit or something from NX or NOS. In fact, I haven't messed with nitrous other than pushing a button 12 years ago on a buddies car. It was fun :). I'm familiar with richening the fuel mixture and retarding the timing. Since I'm running alcohol full time I have my doubts about fuel enrichment in some kind off of-the-shelf kit. I need more fuel enrichment than something tuned for gas.

This is a bit of a stretch as a comparison, but I'll try--Think of an rrfpr for a boosted app. You can change the enrichment from 8 fuel psi/1psi of boost up to 12/1. I'd need something closer to that 12:1.

Basically, I need more fuel enrichment than something tuned for gas. I'm worried about the compatibility of using something that's just "off-the-shelf", even if I DO have bigger injectors installed.

Use a wet kit. It is the ONLY way to do this properly.
Your naturally aspirated Subaru does not need larger injectors, and you are going to have one hell of a time trying to make it run right with injectors that were not designed for it unless you have some means to reprogram the ECU, piggyback the AFRs, or are running a standalone. Leave the fuelling system as it is, install a wet kit with a secondary pump and then size the fuel jet to meet your on-nitrous fuel demands.
Sure, wet kits cost more, but last time I priced a rebuilt EJ25 they were going for $2995.00 :D

probably best trying the nitrous/alky forum mate!
p.s your injectors will be too small! (edit i didnt realise yours was a n/a

there is a thread just like this in the meth/nitrous forum you should check that out

:lol: I wonder when they snuck that in! :lol: