For the money to power ratio, not really worth it. The only way to make any real power with these engines is turboing, and its not really worth it to turbo a 5m. For price of a rebuild and turbo, it would be far more economical to get a 7mgte, then there is also more aftermarket for that motor.
As far as raising your compression, I dont think you are going to be able to raise it that much by shaving the head, you will need new pistons.
As far as raising your compression, I dont think you are going to be able to raise it that much by shaving the head, you will need new pistons.