Skip - How's it going? The big change that I can tell is the bracing inside the main frame rails to the front suspension. Most of what Matt did in the front was gusseting and plating from the main frame rails to the perimeter rails. Then in the back he has one huge plate bolt on plate that connects the two main frame rails together. I know he tried a more traditional X brace, but said it made very little improvement and reduced the already low ground clearance.
Jay - I don't know what Matt is going to charge. Here's his contact info:
www.autoworksracing.com or 619/401-6900. As Skip said they are a custom shop and do mostly high end Mustang restomods. He took his wild Mustang he calls "Obsidian" to Carlisle, PA so it may be awhile until he's back. If you went to SEMA you may have seen it. Twin turbo, 900 hp with the incredible RRS suspension pieces front and rear. He also does a healthy Ford mail order business so there's always someone at the shop.
John