deffo go for the 6.5 matey, in terms of performance it flys like my BII 4.9 doesn't feel much more powerful initially, but i think thats down to the 'smoothness' they dialled into this new incarnation. I use mine for landboarding with the flexi extreme bar..an its a wicked combination IMO, turns plenty fast enough for boarding, fast enough for static flying too, even on the bar. Can get higher with the bar & harness than i could with just the handles.
As for colour, id say Midnight is the best..i bought Petrol, but regret it now..lol