Friends don't let friends install lunchbox lockers.
I've run them for years, and absolutely HATE them. I hate the characteristics on and off road. On road, they make the ass end jump around when shifting and throttling. They make turns difficult, especially when you need to accelerate quickly in a 90* turn, like at a traffic light or crossing oncoming traffic to enter a parking lot.
Off road, they are unpredicable. In hard turns, they don't always unlock. They snap, crackle and pop more than a bowl of Rice Krispies. They cause a loading/unloading that can result in twisted axles splines or breakage. They munch locker pins. Any mod that consumes it's own parts is a bad idea.
Same the money, and install an ARB Air Locker. Since I started using them, there is no other locker IMHO. Ask around, you'll find very few who hate their ARBs.