how much do you want to cover? Last I heard, 3M bought out Ventureshield, so I think there is pretty much 2 options now from 3M, a 6 mil film that is fairly clear, and the 3M Scotch film that is 8 mil (the original 3M ClearBra).
SolarGuard offers the Clearshield product, which has been superior in appearance to the 3M film. It is the preferred choice of a friend of mine that does paint protection film.
Llumar also offers a PPF, but it has been sketchy in appearance off and on. I don't recall the name of it.
The going price here is between $550 - $700 for a bumper, hood, fender, mirror kit. That is the most common coverage package that most shops offer.
3M ClearBra is the most common name, but there are much better looking products. The biggest thing to keep in mind, paint protection film is a sacrificial product. It will get beat up, start to look rough, and will change color. It is a product that is designed to take the abuse that your front end paint would normally take. The standard warranty is 5 years, and it will not look perfect at the end of those 5 years, depending on your driving environment.
It will be nearly impossible to see when the vehicle is clean, but you will be able to see the line where the film ends when it is dirty.
All that said, I am a big fan of paint protection film. I have it on my explorer, and it's been there for about 3 years, still looking great! I think it's a great investment, and will definitely add value to your car.
