There would not have needed to be any R&D for the bellhousing, the new 5.0 uses the same bolt pattern.
Tremec also made all the T-3650s, and earlier T-45s. Borg Warner made them for a while but somewhere along the line Tremec took over production.
At first I thought most of the shift issues people had with the MT-82 was frp, the different gate spacing compared to a Tremec. It felt very similar to my Volvo R car, but as time wore on it got worse. BTW "as time wore on" would be less than a year and 11k miles into my ownership.
I fully understand the accountant run mentality by the auto manufacturers. They all do it, and I don't blame them. They go under the assumption that the money saved in production will not be lost with warranty repairs.
I just don't like having to depend on major assembly production from off-shore when the capacity already exists in an environment where quality of product can be guaranteed. Now true the TR-6060s used in Holdens and Falcons are technically off-shore, but I am willing to bet the Aussies on this board don't mind. Plus a Hollinger box is not really street friendly.