I cut mine off at the bottom "cut here" mark too. Hasn't been a problem for me yet this winter, and I always back off my ramp. Mind you, it's not a terribly steep ramp.
I suspect the problem with the '09's when using a flap that isn't a harder compound like stock, is that the tunnel itself is a tad shorter than most. Unless someone who has tried it can tell me otherwise, I'd see a soft flap stuck in the tunnel all the time.
On that note, I found last year before I cut my flap, when it did get sucked in (which only happened after backing up into snow or something goofy), I would bend it back up right and it would stay. Try leaving your flap pulled or propped up overnight so that sort of forms upward. The flap should look like a cape in the wind - straight back!
I suspect the problem with the '09's when using a flap that isn't a harder compound like stock, is that the tunnel itself is a tad shorter than most. Unless someone who has tried it can tell me otherwise, I'd see a soft flap stuck in the tunnel all the time.
On that note, I found last year before I cut my flap, when it did get sucked in (which only happened after backing up into snow or something goofy), I would bend it back up right and it would stay. Try leaving your flap pulled or propped up overnight so that sort of forms upward. The flap should look like a cape in the wind - straight back!