http://www.sdshobby.com/brushless-combo-for-car-c-26.html
They don't show piricing, you select what you are interested in, register and then they send you a quote of pricing. I have dealt with a lass called Crystal. She seemed to be quite good so when you get around to ordering you can chat to her on sales803(AT)cyclonetoy(DOT)com
I bought two of these for my RC10 gold pan:
http://www.sdshobby.com/ezrun-series-bl-system-for-110-offroad-car-60a55tversion-2-p-426.html
I can't find the original invoice

I think the sytem worked out at around $125 I think the shipping was quite expensive. I can't remember what my old 27T brushed system was like but I can assure you that this is a very fast system. Too fast in fact for my liking or perhaps I just need to learn to handle the power. I have been giving serious thought to finding an old RC10GT to modify to take the spare system. I think the gass truck tranny would be better suited to these power levels.
I use these batteries, they seem to be handling the loads quite well. I set the esc low voltage cut off to minimum to take advantage of the A123 characteristics.
http://www.sdshobby.com/a1233s-96v-2300mah-30c-battery-p-41.html
I have been strapping the A123s down with velcro but really need to design a system that bolts to the holes on my gold pan chassis
EDIT: Almost forgot. The A123 3s was about $14. Downside is that the wire they use is horribly stiff and the shrink wrap is very thick and hard, like a lexan body.