Brushless: Make sure whatever you get is sensored. Sensorless systems are worthless unless you have a monster truck and don't mind losing. I hear good things about the SpeedPassion GT. It's easy to program and smaller than any other (as best I can tell, and in a Pred, space is at a premium). Schumacher is a dealer for them. If you're in Europe I'd look for one of those. If you're in the U.S., I recommend the Novak GTB because Novak's customer support is second to none. I have no interest in LRP/Nosram since I fried a Sphere on a stock motor and it took 2 months to get a replacement.
As for batteries, I'd get into LiPo because you can get such long runtimes and the batteries aren't prone to being ruined if let to sit for 2 weeks.
http://www.trakpower.com just came out with lipo saddle packs that will fit the pred. You need a special charger for lipo, though. Since I don't know where you live it's pretty hard to recommend specific products or stores.