You'd lose all the things we take for granted in the -5 and get:
-Slower rate of roll (most speeds) due to lack of aileron tabs
-Unmodified windscreen
-A more fragile tail section
-Reduced cockpit armor
-A-G ord reduced/eliminated.
-Original cowling (4mph slower than the -5)
This would be offset by: Cooler skins, a slightly
better six view (!!!!) higher ENY and the satisfaction of knowing that Greebo is accumulating perk points he may never use faster than ever before!

Preferably a late -3 model with the R-2800-10W engine (WEP)