If you absolutely do not want to remove the shift knob, then I suggest that you cut a neat slice in the small hole of the shift boot, then pop it over the knob, then place a strong rubber band around the hole where you cut it. Otherwise, If you tear the hole while trying to stretch it over the knob, it might make a nasty jagged tear. You could even punch a nice little hole at the end of your slice to keep the tear from propagating further.

If cutting the new boot doesn't sound good to you, then try heating the boot hole in hot water (coffee-hot) so that it is as pliable as possible. Then use a little soap to try to slide the boot over the knob. I used this method when I put new rubber window seals on my steel garage door. Worked well.

Also, the leather equipped GL models with stick shift came with nice leather boot covers that had a small leather "collar" with a snap button. I have one. Looks nice.