My $.02….. I don’t care for the RPM setup. If you go that route for a cage, the front half is a ‘add-on’. Unless you’re an experienced welder, you will be paying to have that done. The end result will not be tight fitting and consequently half-ass in my opinion. A custom cage by one of the experienced fab shops specializing in these things can fit one that you will not even see unless you get in and look around. You can have removable door bars that do not impede in and out of the front seats. The rear seats are sacrificed with any cage. The other consideration is you absolutely should use a harness for all driving/riding in the car and the roof bars over the doors should be SFI padded.