i just used a on-off valve to control flow, it was fun but the car ended up not making it for other reasons so i ended up not pursuing a permenant installation. a boost switch would be the way to go for sure. there was no "hard" part, run a hose into the intake pre-turbo put the tank somewhere and put a valve inbetween the two
it was as simple as possiable just to explore the concept and see for myself what would happen. it was kinda fun cruising around 20-25 mph with zero throttle input but it ended up being more of a game when i was bored to see how far i could drive without using the skinny pedal.