will interior panels and pieces such as door panels and dash from
a 88 crx fit into a 90 crx. thanks

 

here are some differences im not to sure about the fixment tho
i got the info from crxsi.com

90-91 have a round instrument gauge cover while the 88-89 one is more squarish.
88's have pillar mounted seatbelts,90-91 have door mounted belts, 89 si's and dx's have door mounted belts, 89 hf's have pillar mounted belts.
Models with door mounted belts have a wider pillar at the end of the door to accomodate the belt mount, this also means that the glass is and inch or so shorter.
90-91's have a red seatbelt warning light built into the dome light.
88 has a pocket at the bottom of the drivers door.

 

hardcorepreston is correct on all that info.

you can probably put the 88 dash in a 90-91 but the door panels will be a problem because 90-91 rexes have door seatbelts. so unless you want to relocate the seatbelt than you need 90-91 panels.