i hid my bottle in the rear passenger floor, i cut a slit in the bottom of a gym bag and slipped it over the bottle, i have a kid so i put the hard plastic bottom of the gym bag on top of the bottle and put a few diapers on top, that way when my friends questiond the bag i'd just unzip it and let em see the diapers, they never knew ! i would sometimes ride around with the car seat in just to keep em guessing. hide the nitrous line in the engine inside wire loom and if it's a nozzle drill it in the bottom of intake tube and cover it with loom also, no one will see it