They developed the Ki-61 from their own plans, coupling it with the Daimler Benz engine.
It was misidentified by a "few" Allied pilots early on as a Bf 109, but that was quickly kyboshed by intel.
The Ki-61 was regarded as one of the tougher opponents by the USN, and the USAAF, as it was both faster than the Zero, but could also dive at high speeds. It suffered from mechanical and supply difficulties in New Guinea, and not as many were encountered as could have been the case. Claims of it being cannon fodder is without basis. It was a respected enemy fighter.
Never heard anything about it not being able to roll or turn to the right because of torque, it had a better roll rate than a Zero did at high speeds, and pre P-38Ls did not have high speed roll rates either. I beleive the recomendation was an aileron roll at 300-400 TAS+ vs Japanese fighters generally, since many of them had heavy ailerons at higher speeds, and that wasnt just a tactic for P-38s.
Im not sure what version of AH you guys have, but I think it dives awesome in the game, and holds E very well.