Hyper 7 Conversion Questions

[Tazz]

I picked up a Hyper 7 TQ Sport for $160 new (CHEAP!!! $230 at Tower). I have a few question for converting it. I have a 7XL and a Quark 125 that I would like to use, would this be a good combo. I will probably be useing 4S lipo. I heard that a Kyosho plastic gear will fit the center diff, if so what one and where to get it from and what pitch is it (mod 1, 32p ....). Also what dif oil should I use for each (front, rear and center).