The DD versus Performance versus Race tune question was what I was hoping to find out as well when I posted a while back... so I'm sitting here waiting anxiously!
It seems like people are saying mostly "it's all in the shift points" which kind of makes sense... but not 100%.
I'd love to hear something like "the race tunes give more fuel down low" or "the DD tunes are leaner at part throttle, making them get better highway mileage" or something. Anything, really. Maybe there are so few of us who shift our own gears that it doesn't really matter?