370 watt is nowhere near enough IMO. If you believe the Tahoe Benchmark, the closest scooter to that was the Halcyon/Suex T16. It pulled 393w at max speed. In a recreational configuration, that was good for 187fpm and 40lbs of thrust. That DPV topped out at 179fpm with doubles and a stage, and pulled 386 in that configuration going 150fpm/46mpm. There is some debate on how valid that test is, but it's the best we have, so we'll have to go with that.
At 370w motor, you can assume roughly the same speeds, but that is not a lot of juice if you need to move through any sort of current. It admittedly is more powerful than the mako that was tested at 222w which will stall in some of the high flow caves, but it's a far cry from the 500w give or take that was the "standard" power for most cave diving DPV's.
If you are not concerned about speed, then the 370w is more than likely satisfactory and it's ultimate speed and thrust is going to be a function of the prop and shroud that it's in, but it's not going to be a speed demon.
@victorzamora is far better versed at these things than I am. That said, the motor may be rated at 1700rpm, but depending on the battery in particular, but also a myriad of other factors, it's going to be slowed down by the prop because it just doesn't have enough oomph to turn at its full RPM even though you're giving it enough voltage that it should. If we look at tahoe, which again is what it is, everything is identical between an N19 and the Viper from Silent Submersion except for the battery, but the N19 generates 43lbs of thrust and pulls 465w at 203fpm, where the Viper generates 55lbs of thrust while pulling 673w at 224fpm. Same body/motor/prop/everything, just a bigger and more powerful battery. If you are able to put a more powerful motor in there, at the same speed, it "should" be comparable in terms of power consumption. I.e. if we look at the Magnus which also has the same body/prop/shroud, but has a much more powerful brushless motor, at cruise speed of 150fpm, the N19 pulls 364w, the viper pulls 374w, and the Magnus pulls 387w. That's all about close enough to being the same given the limits of the speed controllers and having to depitch the props, as well as the general accuracy of that test.
So, that all said, if you only ever want to go 100fpm/30mpm and aren't diving in current, then I would say that the 370w motor is probably sufficient. If you are going to want to go any faster, or have to dive in current, then I would highly recommend going to the 750w-ish motor.
