Tom's cage was built by Lucas Fab in Huntington Beach, CA. I have essentially the same cage in my Spec Boxster. I think it's best, strongest cage you can buy.
The link below to Tarett is one way to buy the Lucas Fab cage. Another way is to call Josh Lucas at (714) 317-8393
Josh4130@hotmail.com
15622 Computer ln., Huntington Beach, CA 92649