another crt.5 brushless in progress

I found this forum just a few days ago when searching for information on converting my 1/8 cen matrix to brushless. I had also been keeping an eye out on ebay for a b44 or some other 4wd 1/10 sized off road brushless rc. Then I saw crt.5 mentioned on here and after reading a post or two I had to get one. Picked one up on ebay for $130 shipped w/ brushless motor mount, new tires and foams, and the small hi tech metal gear servo installed. It isn't the long chassis though but since the decent servo was included I went for it.

I want to stick with a123 batteries instead of lipo because I like to run non stop for a couple hours at a time when I go to the track. Time waiting for a battery to charge is time wasted. The key with a123 is having just two packs and the ease of charging a 3s pack in 15 minutes by hooking it up to any 12v supply capable of 10 amps. My charging setup for ac or dc is ugly and cost less than $30 but I guarantee nobody is getting more runtime than me per hour spent at the track :) And I've been a lot in the last few months to compare against nitro and other electric guys.

My goal is to have a quick crt.5 on 3s a123 that can run for close to 15 minutes of racing (or non stop practicing at the track if you wanna call it that). If I go to 4s or higher I need to get a 10amp charger which will run at least $125+. I'll use a mamba max but what motor would be good? I have a castle 4600 that runs really hot on my rustler and also have a used vxl on the way. I'd rather start with one of these motors before buying a medusa. Any suggestions on gearing and motor choices? I'll dig through the old posts now as well. Thanks guys.