Modern "Street Cars" can run the spectrum from docile to insane, producing power is somewhat easy compared learning how to successfully harness it.
Considering the torque output potential of any forced induction engine, I would consider a "mid-plate" a top priority for durability/longevity.
It(mid-plate) should hold the mass weight of the engine and transmission, with flexible mountings at the front of engine and rear of transmission to allow for movement in the chassis.
The factory engine mounting locations were designed for ease of fitment and vibration control as priority, not for trying to restrain the reaction forces of 600+ ft lbs of shaft torque.
If I were to build a 3.8 today, I would most certainly use a block girdle(steel caps would be unecessary IMHO) to make the best of a weak situation considering what is likely to be asked out of it under load, and install a mid-plate to handle the restraint issue.
Best of luck guy's,
Kevin.