The fighter guys weren't that much impressed by the "fighter handling" but certainly much better than a similar sized B-25. I'll look in my R2800 book and see if there is anything special about the A & B model installations. The C version had an elaborate turbocharger setup, housed in the hefty bulge on the bottom of the nacelle. I'll look at what info there is on the roll rates at speed, but a four second roll is considered very good for the era. Lot of inertia there! I don't recall the P-38 being capable of a three second roll. Will research this.
Currently the CH and oil temps might be a bit on the high side. There is existing an instrumented 2 D cockpit that is handy for monitoring engine parameters etc, in addition to the AFSD utility.
I did have a copy of the POH, but think I scrubbed it from my computer recently.