I feel your pain on open rear (well not so open, my late uncle shimmed it tight - old dirt tracker trick). I am considering a SPARTAN locker (325.00) over the LOCKRITE (295.00), both can be setup with simple tools. But I am on the fence for a AUBURN (399.00), but it will have to be installed for a additional cost(125-150.00). I am now thinking that the locker would be scary doing a doughnut. From a G-Machine perspective, the locker could be very scare.... especially around corners...