I will be installing this kit soon. I've been reading throughout this thread and before I give my 2 cents I will explain my setup.
Pre-install mods:
Exhaust system: Tomei UEL Expreme header, Tomei Expreme overpipe, CNT racing resonated front pipe, HKS Legamax Premium catback.
Engine bay: K&N air filter, Zeta performance 3" intake hose, FXT water based oil cooler sandwich plate, ChaseBays SS clutch line(replaces soft and hard line)
Braking: ChaseBays SS brake lines, Hawk PC pads (Motul 5.1 both brakes and clutch)
Suspension: RCE Yellow lowering springs
Wheels/Tires: Enkei RPF1 gold 17x8 +45 / Michelin PSS 225/45ZR17
ECU: Currently running OFT Stage 2 UEL 93 tune (ran E85 for over 5K but was having a hard time starting the car and switched back to 93 for the winter)
Nitrous Setup: NX Stage 2 EFI kit, NX RPM window switch, NX purge kit, NX N20 filter, NOS bottle jacket, DynoTune automatic bottle warmer, NX pressure gauge.
I plan to start with the 35 shot until I can upgrade my clutch as it will be making close to 200 wtq by my calculations. I also will need to retune before hitting a 50 shot which is my goal (timing must be retarded 1 degree or so at peak torque to avoid unnecessary engine wear). NA on E85 on a dyno made 204 WHP and 165 WTQ.
Everything will be installed by a Master Subaru Tech and all the setup was consulted with a NX engineer.
Notes for all of you out there with this kit or thinking about it. stock car CAN RUN up to a 50 shot NO ISSUES, even on the stock tune(time advancing is perfect for a 50 shot in the stock tune, it's safe). Safety measures are always a requirement with nitrous, rpm window switch is a must, purge kit, n20 filter to protect your solenoids(fuel filter is recommended as well), bottle warmer and jacket will keep the pressure stable which is good both in the heat and the cold.
The NX engineer stated over a 50 shot:
1- Fuel pump NEEDS to be upgraded to at least 255LPH
2- Spark plugs need to be replaced for 1 step colder to run 75-100 shot
3- Retarding time advancing IS A MUST!!
Just my 2 cents
#UPDATE#
Started installing the kit but NX packaged the kit with the wrong fuel line adapter size so I'm waiting for the replacement which will hopefully arrive early next week. I had to order a different bracket for the bottle because with the one provided with the kit is really uncomfortable to remove it and I don't want to place the bracket in a position that will render the trunk unusable. I ordered the Single 10lb 15lb Nitrous NOS Billet Bottle Mounting Bracket Kit ZEX NX N2O from ebay which allows you to remove the bottle from the side instead of sliding it all the way to the top. The throttle body plate was already installed and it's amazing how good it looks.