I switch out the fronts with red and backs with black on my cranks pretty regularly. KVD advocated it in his book andallegedly does this with many of his cranks, but I haven't looked closely at his 1.5 and 2.5's he's been using in tourneys lately to see if he's still doing it. I haven't noticed a big difference one way or the other, but if you're switching out hooks anyway, why not?