The door bars should be OK since they are similar to the "example" cage shown in the Chump car rules.
We have the same number of bends and in relatively the same spot as the picture from the rule book. We will have to break out the tape measure to ensure the spacing between the door bars is within the rules as it might be a little tighter than what is recommended. We angled the bars slightly down at the front of the car. This should allow easier entry/exit from the car.
We tried to stay away from S-bends since it is slightly weaker than having straight pipe segments. The overall bending moment is the same since the offset doesn't change (S-bend Vs. our door bar offset) but having straighter sections of pipe should be slightly stronger if they are loaded in compression as they will deflect differently.
Also, making S-bend door bars is slightly harder than what we made. Both give the driver more room and keep the initial contact if we get hit in the door further away from the driver as well.
The main hoop was placed so that connection to the base plate could be welded all around easily. The drivers seat is still well within the outside of the main hoop legs. A lot of bolt in cages for 944's that are NASA and SCCA legal have the main hoop in the spot too.