Here's the plan...
The spacer worked great and the next part I designed is a new side brace that incorporates a mount for a 30mm fan. the third part in the mix will be rear body supports that stiffen the spoiler deck to increase downforce efficiency even further.
I raced on carpet last Wednesday night and the car was the most neutral it has ever been in high bite conditions. I was able to keep up with the mod racers while running 17.5 with boost! I'm really starting to enjoy this car! I gotta tell you that I changed almost nothing from my pavement setup. I reinstalled my rear sway bars and dropped the gearing, that's it. I even ran the same tires ( Sorex 24 deg.) from the freezing Sunday before which I set fastest lap out of all classes. I will post my setup as soon as I fill out the sheet. I didn't even use sauce, it was that stuck without a hint of traction roll. I've had good days and bad days with the E4 but it's never been this good, especially going from one track to another with such an extreme difference in conditions. Kinda scary. just to give you an idea of how extreme, Sunday we ran on a parking lot treated with soda with the temps in the 40-50 deg.F, overcast after several weeks of on and off rain. (low traction and dirty) Wednesday night indoor carpet at Norcal Hobbies in Union City with great grip and a smaller configuration.

Now as far as the bulkhead redesign goes, an aluminum version is already available as stock from TM and Wolf Hobbies but I will model it up with the spacer for those who don't have the TM aluminum versions as of yet but the spacer seems to be the logical part to start with as it is much easier to machine and thus reduces the cost significantly. For now the plan is to provide a kit that will address the rear end from 3 angles. 1. the shock tower spacer 2. side brace and 3. body post deck supports. All will be aluminum but I can provide ABS plastic versions for evaluation at a much lower cost as seen on my car. I will post pictures later today.
I project that the pricing would be as follows but may change for aluminum once I get a clearer idea as to what my costs will be.

$15.00 for ABS plastic per set + shipping
$35.00 for aluminum per set + shipping

I will post estimates for the upper bulkhead once I model it up. The main problem here is that it will require a fairly large piece of raw stock to make a one piece design unless I can break it down to 2 or 3 parts screwed together.