I don't know if I've ever seen a road race car like mine with the battery in the trunk. All similar cars I've seen lately at the track have it where I do. Helps balance out the driver wt. Not sure about the venting though, I'll check the rule book. They require and in some cars prefer marine non conductive cases. My wiring goes direct to the cut off which is on the PS main hoop on a plate.
Wiring is all inside the car. Similar to my buddies car. (pics)