Need Pictures...
Be careful trimming the carpets near the driver's pedals. You need to make sure that the carpet cannot hang up the pedals (Toyota sudden acceleration syndrome).
Also for making holes for the seat belts. Get an old or cheapo soldering iron with a tip you don't care for. Go from underneath and use the hot iron to melt holes through the carpet for the front seat mounting and all seat belt holes etc....
Clean or replace the tip on the soldering iron when done... It works better than trying to cut the holes with a utility knife.