Here are a couple of Bolt-in's
I have seen the STI Cage in an 02 wrx from vancover it was a decent fit and the guy used it to road raceing.
Depending on the type of racing there is a good chance these cages will not pass tech...
For example from cars rule book
(f) Required Reinforcement
(i) Bends and joints:
Gussets or corner braces joining the front continuous tubing, whether front rollbar or
lateral rollbar, and the brace tubing are required. The gusset or brace shall span the
weld that joins the two tubes and may be positioned either in the roof quadrangle or in
the windshield area.