I have carpet in my truck with a fairly thick pad for noise reduction.
so do i
i bought a jeep shift boot ring, pretty simple ring.
ANY ring will do as you will hide the thing anyway.
mocked up a paper shaped cone the height i wanted.
I made a hyde-o-nyga shaped (my color choice) cone @ the upholstery shop.
added about 2'' more for the material to go round/under the ring. he sowed it in about 10 minutes. I turned the stitching inside. i used some foam insulation to keep the noise down.
bolted the newly made boot & attached ring to the carpet after slipping the top part of the cone over the shift rod.
i used a couple fender washers under the carpet.
we're good :p