Well that is your decision, as for the HDD the green has its own problems compared with the blue. As for unlocking the cores I hope you know what you are doing because all I have seen is with the 720 X3 and unlocking the 4th core.
what goes around comes around
(RIG)GA-EP45-UD3P, Q9550 @ 3.5 ghz, CM's V8, HD2600XT512mb 128bit, 4gigs OCZ 1066 ddr2, Seagate sata 120 gig & a 320 gig, 2 Liteon sata DVD Burner, My DIY Case, Corsair 550watt PSU, 2ea 19" LCD monitors.