Would this boot be too stiff or overpower at BD 03 freeflex binding?

03 would be too soft, but I ski a freeflex small on 02 and also a midstiff on 02, and they work fine in the resort setting. I think the mid stiff is actually better. But I think the "ridiculously" stiff would be way too much work and take too much strength...unless you are racing or skin in deep heavy powder only. This is from a 115 lb 5'3" mostly tele bump skier.

Waaaay too stiff. If you're determined to stick with these boots, go for the Black Diamond 02 binding, using probably the Rid Stiff cartridges. Maybe if you're under about 120 pounds go for the Mid Stiff, but even those might not be stiff enough. If, on the other hand, you already have Freeflex O3s and want to get boots to match that level of aggression, go for the Axis or the Trance, or even the Scarpa T2 or T3.I would disagree, I ski these boots on the BD O1 with the free flex and LOVE it (I weigh a lot more then 120lbs and have it mounted on the 07-08 Verdicts). The boot is stiff but the flex of the bellow isn't overly stiff. With the 03 you may be better off with a mid stiff, but if these boots fit you well then try it and it's only something like $40 to get a new set of cartridges if you want something more active.