If I ever (find the time & extra cash to) build a spec racer,,,,,, I will cut the body in half.
Looking at it, the quick-easy way would be to do it right at the mounting point on each side before the rear fenders. (right in between the body mounting bolts)
I would also order a "spare" body for my car & have it cut/painted & ready to mount, so that there is nearly no "down time" or missed races due to body damage.
There are also alot of other "little tings" I would do,,,,,,, some I will share, but the others you'd have to "beat" out of me