The left side is completely fine for some reason, but on the right side from about the halfway point to the back its rotten.

 

from another right rear bottom piece from a different EF civic that isn't rusted out

 

cooilio, Ill be looking.

weld in rear quarter panels are for sale online but they're pretty pricey

either Ill get it off a parts car (most of them are rusted out since im in ontario)
or ill keep looking for a weld in quarter panel piece, but Ill probably have to make my own plate for the part thats rusted further forward

 

Less than $80

https://www.millsupply.com/auto-body...l-2128840r.php

 

carparts.com has them fairly cheap
ordered the whole quarter for my 89 si hatch and its an exact fit