The aero kit is the extra body cladding (deeper front airdam, side skirts, rear underbody spoiler, trunklid wing) that the dealer can install. Usually I can't stand bodykits, even from the manufacturer (including Honda) because they look like cheap addons. The 2k6 Civic's body kit isn't too bad. I actually sorta like it. I saw a 2k6 EX sedan a couple of weeks ago wearing the bodykit. Fairly sharp. I wouldn't get the big trunklid spoiler installed though if I wanted the kit, just the lower pieces.
Look at the car in the upper left hand corner in the link below. It has the bodykit installed.
http://www.collegehillshonda.com/civ...lectronics.htm