Location: I live in the Heartland of the United States - Western Kentucky
Because glass is a better conductor of heat than most metals (don't include enamel-coated cast-iron), the oven should be a bit lower. I use glass pans for my bread and always turn the oven down by 25 degrees.
"As a girl I had zero interest in the stove." - Julia Child
This is real inspiration. Look what Julia became!
Pyrex does not have a recommended temperature. They do however recommend you follow your recipe instructions when cooking. Glass does cook foods much quicker then metal bakeware. The great thing about glass bakeware is that you can see through it so there is no need to change the temp just watch it more closely.
It doesn't have anything to do with "Pyrex". It is baking in glass that requires lowering the temperature 25* because of the better conductivity of glass over metal. You can use at higher temperatures, of course.
Sorry, just saw that Katie said much the same thing.