Can you post a link to the 'crystal' changing? Haven't heard of this before. To be honest (and I'm not nit picking) I'm not sure why you would want to remove the limiter - they make less power at red line not more, usually peak power and torque is lower down. If you've modified your engine so need the revs then really an aftermarket ecu should be on the cards as the stock tune is more than likely not up to the task.