thanks for th equick response there wayne.
I've just been doing some looking, and I noticed that Hi-Tec do a very cheap, and lightweight servo (the HS-81MG). I was wondering if this whether this would be suitable for 12th scale? the only problem i can see is that it doesn't have ball bearings in it, and possibly its durability in the car (it's quick, a 0.09sec, and torque seems good).
Anyway, I've got some spare packs of 6cell GP3300's here, that i'm gonna break up to make into 4cell packs, so that sort out batteries, i guess for now i'll leave it without a reciever pack.
Ed