I am new to this myself and am upgrading my losi xxxt to brushless. I know your car is a buggy, but the setup that I am getting is the Lehner 4200 and MGM 80. I am not sure about the Warrior, you'll need to ask Mike about that.
If you want cheap then go the novak (no exp with it though) as you get the motor and esc together or the feigao (again no exp just looking at prices).
For gearing the site below helped me.
http://www.rcuniverse.com/magazine/a...article_id=506
As for batteries, I read that you can get matched and zapped cells for racing or standard cells (unmatched) - this is probably the best choice for bashing (i.e. running about the neighbourhood). You can get your batteries off Mike or elsewhere (
www.maxamps.com). GP3300's
Anyway, I have found that just reading forums like this and taking time to speak to mike and others really helpful in deciding what to get. Hope that helps :)