totally agree, its going to cost the same setting it up whether its a brand new car or something older, yet similar. but with all respect i think this gentleman is just starting out so a 125-200$ racecar might be a bitter pill to swallow whereas a <30$ prebuilt racecar is something he can quite comfortable learn in without the fear of costing more than a riviera boat! why aren't you doing the hard sell on your car brendon! (even blind freddy could see im trying to help ya!)

as for rollcages, if you got someone like steve maitland to build you a rollcage that has all the bells and whistles (bear in mind the car is already stripped out) you wouldn't get much change out of 9999$ so by the time its painted and all the trimmings go back in/modified (unless you go carbon so add +++$) its another 5 grand. of course the DIY approach favours those with skills and time, the likes of me have neither so we to rely on others.