To avoid this issue, you should have just gotten the stock knob, they're not hard to find since they used the same knob for the Civic 88-2000.
You're going to need something to fix the boot sag...Acura has a adapter kit, which is made for the RSX when you use aftermarket knobs, but applies in this situation.
Two places i know have this, but one place never answers emails, and one place is super overpriced.
If you could hunt down the part number for this, you can prob buy it from Acura/Honda.