There is no drilling on the cage. They use a sonic tester to determine the gauge of the tubing and use a template type of gauge to check the diameter. If the cage is not legal you won't be able to run it in classes that require certification, which I'm not sure but I think just about all of the NHRA classes do now. If the only place you want to run it is outlaw tracks that don't require certification then you don't have to worry about it but the car will be more difficult to sell. I would stay away from a non-cert car. If you find one that hasn't been checked that you are interested in you could always strike a deal on the condition that it will pass and pay to have it checked. If it fails the money you spend on checking it will be money well spent.