Lipo : I would suggest 4s lipo for either motor. The polyquest 6000 25c cells look best. You would need 2 2s packs, one for each battery tray.
I run a 1515 1.5d with a MMM and 4s worth of trakpower packs. It runs great, but I feel that I am close to the lipo spec with that setup. They are 4900mah 25c lipos. That is why I feel they 6000 cells would be better.
As for gearing, I run 19/50 mod 1 gearing. You can use MGT spur gears to convert over to mod1. You do have to mod them slightly. The center hole of the gear is close to 10mm, so you have to replace the stock slipper bearing with a 5x10 bearing (same size as most nitro clutch bearings), the stock revo bearing is 5x11.
You also have to enlarge 3 of the holes on the mgt spur to 5mm. This allows the spur to fit flush to the slipper hub. The hub has raised bosses that are threaded for the mount screws that hold the gear on. If you line the mgt spur up to the slipper you can see the 3 holes that need to be enlarged. Really easy mod, takes about 1 min.
You may also have to SLIGHTLY enlarge the center hole of the spur to fit the 5x10 bearing. I use a body reamer and take off a tiny bit of material till it fits tight.
Spur link :
http://www3.towerhobbies.com/cgi-bin...ster+GT+SPUR++