i'm not going to read all of this thread, but i will put my $.02 in.

WD-40 is a lubricant but a very thin momentary lubricant that does not stay where you spray.
it's also a penitrating fluid for rusty bolts or to free rusty links in chains or to free up otherwise stuck moving parts.
it does stop squeaks but is also petroleum based and will once it soaks in to rubber/plastic parts or seals will ultimately result in their destruction.
keep in mind that traxxas is a company that survives on your dollar.
to me it would make sense for them to have you use this as an after run oil cuz in the short/long run it will destroy the seals in your engines. then they get more of your dollar for repairs.
if this was not the case ,all their RC's would come RTR will every available hop-up and they would need nothing and still cost about the same.
basiclly they want your dollar.
most after run oils however are also petrolium based as well but are better suited for our needs in these engines.
they do all the same stuff as WD-40 but with a thicker viscosity.
plus it doesn't gum up like WD-40 when it sits.
there are a couple brands of after run oil out there that are silicone based and will protect the silicone/rubber seals in your engines.
as far as WD-40 helping the plastic parts of our RC's, guess again, in two three years or less the parts will get brittle and start looking like an old dash board of a car that sat to long in the summer sun.
i've seen it happen.
www.rbmods.net has silicone based after run oil for this purpose and it works fantastic.

oh, and it does NOT eat bearings, it eats rust and protects metal from rust.
can also be used as a coolant for drilling, milling, cutting, etc............................................... ......................