Obviously I'm not qualified to answer and have no data on the matter. But historically larger displacement engines tend to leave more on the table for tuning gains. I would suspect the 3.5 would show better gains than the 2.7/3.0 (but that's based on absolutely zero real data).Maybe Livernois could chime in and give us an idea of the potential of the 2.7/3.0 compared with the 3.5. They are much different engines but which one has the most tuning potential?