So I have a 00 maxima with a 5.5 gen front... and was told the foglights are different from the 5gen... how are the fog lights different.. and can they not be interchangeable?

Not sure how, but for sure they are different. You need 02-03 fogs

They mount differently.

It will fit the bumper but the connections are different. When you try
to put a 00-01 fog light to a 02-03 maxima car, the plugs are exactly the same so it will not clip in.

00-01 foglights fit differently from 02-03. They are also made from different types of materials.

00-01: Plastic Lens
02-03: Glass Lens

Lol, if we could use the 00-01 fogs in our cars, I'd have those in a heartbeat.