I have a '90 Maxima. How can I tell whether it is a GXE or SE?

look on title or regestration card,look on back of trunk,or call insurance agent.

Yes, your insurance company should know since they can read the VIN and decode it same as a dealership. Typically, the GXEs are marked, the SE's are often the "base" model and will not be marked as such.

metal plate on firewall. engine code VG30de =gxe, Vg30e =se

i had a 1991 se.... the gxe model had an automatic tranny with an adjustable suspension. just in front of the shifter there is a switch to switch from "comfort" to "sport". the "se" model did not have this since it was the "sport Edition", and the suspension was as if it was set to "sport" mode all the time. with the option it was not quite as sporty as the "SE" without the option, and it was not produced on the "SE" model since it added weight to the car and slightly changed the balance distribution. Nissan thought it would be more sporty if the car was just constantly "geared" for tough cornering. and also...most "SE's were sticks, if not all of them....so if you have an auto, chances are its a "GXE", if its a stick, chances are its an "SE".