i used corrosion X on the PCB's in the rx and servo, a dab of marine grease on the gears inside the servo, the speedo was already waterproof, i stripped the batts packaging and let them dry out for a week

it was all stock apart from the servo, rx and batt, the batt was a 2.2a turnigy 3s and aslo tried a turnigy 3a 2s