[Tesla]

I am just about happy with the mods on the front end, into version 3.2 now, have partial front skirts fitted and have been looking at what to do with the rear end, at this point considering a small Kammback 6-12 inches on sides and top, diffuser is an issue as the tow bar position restricts this to a max of about 6 degrees, but need to decide exactly how the rear underside and rear wheels will vent before starting on the kammback. I have material ready for the rear skirts, but wondering if I should allow for venting into the rear cavity or just let the air find its own exit.
Being a 4x4 the rear wheel cavities could house a bat colony so there is quite a bit of air tossing around in there, there are also large gaps in the inner guards that let air flow into the rear underbody above fuel tank and around the chassis. I have seen some designs which have special vents to jet out rear wheel air at the back and help with clean seperation.
The easiest solution is to open up the rear underside and let the air flow out under and over fuel tank, towbar etc., but is this the best option?, thinking the answer may be no, but to block all the holes above towbar would drop the air release from the underside at pretty much axle height and this doesn,t seem right either.
So what to do??