I bought a 2010 Subaru Forester two days ago (yeah!) What are the best products that I can buy to protect the paint/upholstery that I can apply myself ?
Car wax for the paint. Any brand will do.
Scotch Gard or similar will work for the fabric.
These are the same things the dealer sells for several hundred dollars. You saved a lot by doing it yourself.
The best thing you can do for your new car is read the owher’s manual and follow the recommended service intervals.