Get some heavy duty 2" wide Velcro, and connect the bottom of your cut foam wedge onto the existing carpet. Then lay your normal floor mat over that. It will not fit well, so I'm temporarily using an old Lexus one I'd hand cut from a piece of rubber I got from Home Depot years ago. Once I find more, I'll re-cut it to fit better. Velcro of glue it to the other mat. Use E6000 glue, amazing stuff. Can be removed if necessary. This extra mat will (A). help lessen road noise, and (B) allow you to cover the old mat, with an overlap that covers the foam piece as well. Make sure you cut it short enough that if it shifts, it can't interfere with the pedal. I take no responsibility if you cut it wrong!!!
