The Wheelie King (aka Crawler King) chassis was pretty quickly recognised as a capable crawler platform therefore there's heaps of info on this one as well as plenty of mods to be had. Check
RC Crawlers WK forums for more info.
I've had a few HPIs and they are good gear; not quite race quality but they have another brand (Hot Bodies) which they have won plenty of big races with. HPI parts are also readily available in Aus - if you're not into mail ordering from HK/US to save some pennys.
I've done the liquid electrical tape coverage on both my Transceiver (radio receiver like thing in the truck) and Brushless speed controller; have had the truck pretty wet with no issues although should be submerging it for extended periods (in Merri Creek) soon.. hope to have pics & footage.
Although I am a self confessed R/C geek/addict I'm still not sure why I should have used liquid electrical tape instead of silicone sealant, hmmm.