Well... technically...
The AM chassis was manufactured by a company called Holden Aluminum Worcester which is the same company that manufactured the Lotus chassis. It was a private company for years until being sold to Hydro Aluminum (IIRC) and Lotus, (yes, that Lotus), who purchased the Holden Lightweight Structures division and renamed it Lotus Lightweight Structures.
The engineering, tooling, and production of the AM, BMW, Jag, and Lotus chassis components was performed by Holden (Lotus as of 2008, if you're keeping up).
All that neat stuff people think Lotus did as far as technology with the chassis? Most of it was Holden - they do some mind-boggling stuff with aluminum: compound bends and twists with extrusions, etc.
As to the split between the development and production engineers?
