Basher Truggy Oils?
 

What diff oil weights should I use for my Hyper ST with mashers with a 1515 on 5s for bashin and jumps? What's a good starting point?

I usually try out what is included with the kit and go from there. Generally softer springs and thicker oil will provide a plush ride, but will have body roll. Thinner oil and heavier springs will be more bouncy off jumps, but should hadle smooth areas at high speed well.

In this video, at 13 seconds, does that package contain shock oil?
http://www.youtube.com/watch?v=y8zt1qOfqpM

I am sure that the kit contains shock oil.

Main question is, does it contain diff fluid?

Most of the time you have basic 300 or 400 cps oils provided for shocks, and grease for diff. But heavy silicon oil for diff isn't provided. Best choice would be to pick 3 most common grade

3000
5000
and 7000

Most of the time thickest oil add motricity but you lose reactivity in corners.