from the bottom of the car you should only see stuff like the subframe brace, oil pan, transmission, fender well splash guards, and suspension. Maybe you thinking of a skid plate? integras never had those lol
jhpusa used to sell an under engine guard. i think it was made by benen. cant remember the right name for it but its not an oil pan nor is it a stupid spash guard. found this when i was searching for the actual name of it cause theyre not selling it anymore.
it used to cover the entire underside of the engine bay area to prevent rocks and crap from popping a hole in your oil pan and such.