Those numbers are about right for the best Euro 3.8 and the worst US 5.0. You may however find the 5.0 to perform similar to the 3.8 only due to a wider power band. You can find that data on the 107 CD under the engine section.

What would I do??

I would sell both engines and get a nice low milage 5.6L M117.

John Roncallo