I have no idea! I am asking you guys!
PS: I just cut a big hole through my car. It's real easy. Drill a couple of holes. Then another one right next to the first to make room for the saw blade. Rip a couple of big cuts with a cordless sawzall. POOF - a hole!
I made it big enough to fit my head through so that I would be able to easily see where things line up above and below the car.
The gray tube is plastic conduit which houses the cables running from the back to the front of the car. I made sure NOT to saw that in half while cutting this hole. (Please note that I did, of course, unplug my battery disconnect for doing this!)
This is an "exploratory" hole in the car. The final cut will be done with a plasma cutter, or at least using a straight-edge. I did NOT want to make too big of a hole right now, but I do need to figure out where the suspension lines up, etc.
Also, I may have to replace rusty brake line or do other work while it is easily accessible.
Now that I think about it, I HAVE built a super-eco-friendly vehicle. Just "Fred Flinstone" your way down the road!