so I drove around for 20 minutes with just the MPPK and so far I feel like it is similar to RC ultimate at setting C but it feels more smoother? I don't know if that makes any sense. I can feel the instant torque low end power and I really like my X5 now. I'm still contemplating if I want to add RC or not. I want to drive around with just the MPPK for a week before thinking about adding RC just to get a feel of the new tune for a bit more.