While it would certainly be a painstaking project, installing the 3.8l Supercharged motor in a G body would make a sweet ride IMO. I've had a number of Bonneville SSEI's, Grand Prix GTP's and Regal GS models over the years. Smooth power and great mileage, only about 2 mpg less than a stock 3.8. 240-260 hp in stock form, but there's probably another 50 hp to be had with exhaust and programming upgrades without destroying the driveability.
Bill
Bill