Firstly i'd reccomend a Hobbywing WP SC8 120A ESC:
http://www.ebay.co.uk/itm/1808829265...84.m1439.l2649
I've used this in Monsoon conditions in my HPI Vorza several times and it's still going strong although you might want to temp gun it regularly on a really hot summer's day because being encased in resin makes it run a bit hotter than the HW 150A XERUN. I've also just fitted one to my 1/10th buggy as they can be re-programmed to run on 2 cells and do everything a 1/10th speedo costing twice as much does.
Also i'd say get a Leopard motor, just because they're cheap, fast and easy to take apart and re-lube the bearings after they get wet:
http://www.ebay.co.uk/itm/2508233990...84.m1439.l2649
Lastly it's always good to have a cheap servo so it doesn't matter if it gets wet and you can keep your best servo dry, ToiletPro MG996s are ideal for this purpose:
http://www.ebay.co.uk/itm/3706710488...84.m1439.l2649
I've used this setup on a lot of wet race days at South Coast RC in Ringwood and it's never let me down even when aquaplaning through 1-2" deep puddles on top of the astro. As long as you protect your receiver it really is possible to make an electric buggy more reliable in bad weather than a nitro. Enjoy
