The shifter is easy enough to remove, so IMO, it's both easier and safer to do that. If you want to cut around the shifter without removing it, you'll have to do some pretty advanced eyeballing to be able to cut it in the right place. Don't think it will be possible to measure the location either, as there's no good reference to measure. Most carpets I have seen have been oversized, and you won't know by how much until it's in place.