Outer Limits 4x4 Board

i have a 80 series toyota
i have the following
a boss compressor
a 21 lt tank
a adjustable reg to 150 psi
switchs and relays ect..
where to mount it all
under bonnet boss and reg under floor 21lt tank
water damage to boss ? track damage to tank ?
or
in rear 1/4 with tank & boss reg ect
loud in car ? more wiring less space in rear for gear

i had my boss compressor inside the cab and made me jump everytime it turned on so i mounted it behind the winch , which brings us to water damage and i can safely say that driving through water deep enough to be parting on the widscreen that water doesnt worry the compressor , although it wasnt running whilst under water , but when i got home ( about 5 mins later ) i started it up and it ran fine , but i do want to extend the intake and aircleaner like a snorkle then it should run under water ( in theory ) , i wouldnt worry too much about the air tank as they are pretty robust and can take a decent hit , mines mounted to the chassie rail and so far so good