Yeah I'm with 67autocross on this one. Once you get the header flanges much lower than about 3.5" off the deck they start to drag on everything if you're driving it on the street. And much lower than that will actually hurt handling, because you don't have enough suspension travel anymore. Even with the 1.12" bars on my car I need the 1" of travel I have to the low profile bumpstops. I don't bottom out very often but it does happen occasionally. Bottoming out frequently equals crap handling, not to mention a lot of wear and tear on the suspension.
Can't get around the math. If the header flanges are only 1.5" off the ground at ride height, when you bottom the suspension out the exhaust is pretty much on the ground. A 1/2" of travel at the bumpstop is more than that at the wheel. I'm surprised you can drive the car like that at all. Around here the potholes are more than an inch and a half deep. High centered on a speed bump. I like low but it has to be functional.
