I see you are new here, so let me be the first person to welcome you to the Acura-Legend forums.
Performance parts, basic "bolt ons", there are a few.
Weapon-R makes an intake for our cars, labeled as "strictly 5speed", however, some folks have made them fit (including myself in my old 89 coupe) automatic transmission cars. The automatics have a throttle cable metal that sticks out and makes it EXTREMELY hard to install.
Also, for exhausts, there is Stromung (www.stromung.com), direct fit, catback. Really nice low rumble. (2 door only I believe)..