Challenge team owner?

Hi,
I work for a company that builds and repairs race trailers. I am currenty
doing a remodel on a trailer that was once owned by a gentleman who
used to supply cars for the Ferrari Challenge. I am looking for any
information on the team owner and and maybe some cars and drivers
that raced for him.

The guys name was Letterman. I believe his first name was Michael. The trailer
I am working on was built for him in 2002 so I guess he would have been active in
the sport in the late 1990s and early 2000s.

Any help you could provide is greatly appreciated.
Thank you,
Greg