How many of the add on kits were sent to the dealers?
There were a few field install jobs, but dealers shied away from competing with the factory plus the parts bought individually in primer cost as much as the package's dealer cost. Remember, this program was all about matching the Cobra II program at Ford.

What vendors, if any, were used for producing the associated parts?
The body parts were made in-house using Mobay Rim 110-50 elastomeric urethane (50,000 flexual modulus if your into that sort of thing).

The primer and top coat came from PPG Industries. The decals (very problematic) came from Sparcal in Holt, MI.  

The decals were screen printed on vinyl to the Chevrolet colors and design.  The vinyl came from Stouffer Chemical who was a 3M competitor at the time.  The adhesive on the vinyl was unstable and allowed the vinyl stripe to shrink on the car.  Some stripes were fine, others shrank and it was a mixed bag. A car may have one or more unstable stripes.  We field repaired everyone at Stouffer's expense. They soon after left the OEM decal business to 3M.

All the mounting hardware and misc. packaging was vended locally in Grand Rapids.

What was the last known disposition of any unused stock?
Used up, We maintained the service parts requirements for more than 10 years to the point that GM was no longer interested in following them.

Was the tooling at MATC or an offsite location?
The only outside vendor was a contract painter.  The parts required an elastomeric paint from PPG that matched the flexibility of the bumper covers.  Very difficult quality requirements eventually forced us into becoming a very sizable painter.

Who did the initial prototyping, GM, BORT, or MATC?
We did the original proposal on my SCCA showroom stock Monza at BORT's meager studio in the warehouse of Shane Steel on Eight Mile Road in Hazel Park. The final design (clay model) was done in Chevrolet Studio under the direction of Jerry Palmer. We took the clay to Hoard Pattern in Detroit and they produced the Kirksite Molds for the program.

How far into the '78 year evolution were the cars taken before cancellation of the program?
There was never a "78 program.  Problems with the name and field problems with the decals killed the project.

Were any other color combo (other than the RW&B)  or prototypes made or sold to the public?
Production colors were (these four colors represented about 80% of all Chevrolets produced.) :
White with Red & Blue stripes
Black with Gold stripes
Red with Gold stripes
Silver with Maroon stripes.

Do you have any memories of a prototype made with a "whaletail" rear spoiler (owned by Dick Baumhauer)?
My original SCCA Showroom Stock 4 cylinder white 1975 white Monza 4 cylinder 5 speed with maroon interior was the prototype and it had a Carrera style whale tail and aggressive wheel flares.  Very cool, but not Chevrolet.  It was called "Rapide" like a pre WW II motorcycle.  Chevy didn't like the name, so they came up with "Mirage."  Chevy legal staff thought they owned the name, but about a month into production, we were served by a guy in Phoenix who claimed ownership of the "Mirage " name in Arizona.  His father was a prominent patent attorney in Chicago and figured our how to out smart GM. The basis of their claim was around the Gulf Mirage raced at LeMans previously owned by John Weir.
I don't remember what I did with that car.  I replaced it with a Cosworth Vega purchased like the Monza from my friend Dale Berger, Jr.

Was it basically lack of sales that ended the program?
No, field problems with the decals killed the project and especially the problem with the name killed the deal. The royalty demand for the "Mirage" name was much higher than GM was paying SCCA for "TransAm." Today, "Mirage" is owned by Mitsubishi.

Was MATC involved with any other H-body special programs or do you know the names of the companies that were?
MATC existed for a short time, about a year.  We bought the BORT shares after the end of the Mirage program and used the plastics molding equipment to develop C&F Stampings eventual position as the number 2 non captive source for reaction injection molded bumpers to the OEM.
At C&F we developed design and engineering capability that platformed off the experience with the Mirage.  We developed the Firenza for Olds from scratch including clay molding.  We also had a bit on the Sunbird.  Eventually, we molded the Monza Spyder bits for GM Parts Division.