[oberon476]

However, they also mention something about temperature changes. Anyone know anything about these temperature issues?

Adding the film to the inside of your windows is going to make them hotter in direct sunlight than they would be if the solar heat was allowed to pass directly through the glass.

If you have single pane glass then you probably won't have any problems other than the glass may be hot to the touch, but if you have dual pane, especially with a LowE coating on the glass, then the increase in heat due to solar gain can be substantial and worst case could damage the insulating glass seal or even crack the window glass. The potential for glass breakage increases significantly if you scratch the glass with the razor blade as you trim the film after it has been applied.

Adding an aftermarket film to windows that are under warranty is probably going to void that warranty. This is pretty much universal if not 100%, but on the plus side many thousands of people have applied aftermarket films without any problems, and some film manufacturers offer a warranty to replace the original voided window warranty...something you might want to check on. On the minus side, the darker the film the more likely the potential for problems.