Where do you live?
Getting your boots set up right makes all the difference in the world. Getting the forward lean right, getting the cuff cut down to the right height, getting something that's got the right hole size so you don't have to buckle to tourniquet tightness is all really important. While there's certainly some variation, I have a suspicion the big flex variances you guys are reporting are more due to boot setup issues than raw stiffness. Svend's 220lbs should easily flex anything out there, if it's set up right.
If the boot's so upright that you can't get past that camming angle to the point where you can apply pressure to it, an 80 flex boot will feel impossibly stiff. If the boot's set up right to let you get on it, a 150 flex boot feels pretty darned manageable.
If the spoiler doesn't get you past the bouncing point to one where you can flex the boot, I'd second Gary's suggestion of loosening the top buckle. I'd only loosen it by one notch though, and I'd use a Booster strap against the liner tongue cinched pretty tightly. That way, you're skiing mostly on the Booster strap (which is comfy and gives you a more progressive feel), but have the rest of the cuff there for support when you get really forward and want to drive the tips.
Okay, stepping off my soapbox now..