Thats probably whats holding it back, stick a 100mm core in there. Everyone i have spoken to has said you need a thick intercooler if you want to push 400+ from the 35R
the ice box would be for dyno runs/drags, if its just plain water to air it could be used all the time, what intercooler do you have at the moment dave? 100mm thick core?
theres your problem. no clutch slippage. you cant just expect it to grip and go without wheel spin or bogging. abuse that thing like a red headed step child.
go for a heavy duty organic over a button so you can slip the clutch with decent revs to get you off the line, revs and dump doesnt work with street tyres + rwd
a cop looks under the bonnet/in the boot and sees a nos system and you are farked, this isnt the USA you cant have a connected nos system on the street legally no matter who you get to say its safe.
all the things you are listing (except the baffled tanks) snow performance have been doing for a while, my kit (which was 3rd hand when i got it) has solenoid controlled flow based on boost pressure (albeit not in the nozzle itself)
i dont have any pictures of the lines going from the boot to the engine, i just drilled a hole in the boot floor, fitted a grommet, stuck the line through and ran it with the fuel lines.