I don't knwo how many turns the stock ones are. but yes you would have to get a reversed one. The reversed one goes in the front. luckly.. Kyosho makes them in
standard wind and
reverse wind. They are a little bit longer than a 540 motor. I used to run one in my HPI Nitro Mt for roling around the house and crawling over stuff and will be running them in my ClodZilla. They have lots of nice smooth low end torque.