What's the speaker size for 1997 altima gxe?

5 1/2 for the rear and 5 1/4 for the front. --------------

The rear speakers changed at some point in the 97 production year. Later model 97s have 98 model year speaker sizes. I believe early 97s had oval rear speakers, late model 97s had round ones, can't remember specific sizes. Look at your rears first to see the shape of them, then when buying new ones check between 97 and 98 model years.