Been in the game a while, and a few years ago, realized that 1998-00 Civic's with a/c had a more modern ventilation box, as do the Canadian Acura EL during those years, with a full provision for an oem cabin filter. The 1997-01 Honda crv came with the option standard, as did the EL, and civic models oversea's came stock too. If you hit up a pick n pull, and 1st generation Honda crv, you can pull the box open behind the glove box and pull out the filter and brace it fits into. Often you would want to put in a new filter though.

Anyway, low and behold, i was parting a 2000 Integra today, the dash was out and i noticed the airbox "had" the provision for a cabin filter also, wow. Great upgrade for cheap for those interested!!!

 

My 1995 Integra already had the door as well. It was just missing the tray and the filter.

 

Yeah, it's weird that in other countries cabin were standard, and most Honda and Acura models shipped to North America in the 1990's just had a void there, instead of adding a very inexpensive feature already designed to be there