pan makes no difference on a crossfire...and I don't know how yours flows in an air chamber with no rear wing, I wouldn't think there would be a lot of downforce at high speeds...the front bumper cover on mine is shaking like a leaf at those speeds trying to keep it down...the "drip pan" is just that, a drip pan...each to their own, but we have been up there numerous times in all kinds of windy conditions...the vette I had was more solid, but the XF does just fine. I have a trucking buddy with a car like yours, he bought for his wife...and they are very similar, but not the nose or lack of wing in the back...I just dont see it being a high speed car...nothing to hold her down...now the newer models, seem to have more rake in the front, and more styling for high speeds...the way it is configured, it just looks fast setting there