Good paint match!
The problem is, with a base mounted to the body, and a driveline that still can move (aka not solid bushings) it will twist and tweak around a bit, leading to a shifter that changes feel, and possibly lead to some botched (money)shifts.
Edit. Gah, just reread your mod list. You say solid motor and trans mounts? How can you mount it solid if the engine has knock sensors? It's gonna register every nook and cranny of vibration and pull the timing right out...