The lighter weight of the Borgeson box is a great plus... 10 pounds here, there.. especially off the front end, all adds up towards a better handling modified vehicle. IF this were "legal" in the club racing rules for the specific classes that I choose to run, which, unfortunately it's not for my present classes (SCCA E/SP, and others), I'd be most interested I doing this swap.
The only down-side I see with the Borgeson box is that the steering turns lock-to-lock (3.5?) is greater than the T/A fast-ratio box (2.7)... and fastest steering is what's needed E/Specially in pylon autocrossing.