A list of hidden or missable cars in Saints Row 2:

General's Limo (Hounfor) - In the last samedi mission, run over to the General's limo when he jumps out of it, get in the limo and quit the mission. The Limo is the only one of it's kind in the game.

Military Wolverine - In the mission for the brotherhood "JailBait" after blowing up the prison buses, go to the airport and 2 wolverines will be sitting there. They have unique paintjobs. Get in one and quit the mission. They are black with military stars on each wing and on the fuselage, and a monsterous face on the nose.

Racing Edition Of MonsterTruck - In the Brotherhood mission "Bank Error In Your Favour", once you drive over to the Demolition Derby Arena, don't enter the blue marker. To the right of the blue marker will be a monster truck with racing stripes and a flame on the bonnet. Get in it and quit the mission.

Brotherhood Helicopter - In the brotherhood mission "Enemy Of My Enemy" Once the Brotherhood start arriving, when a helicopter hovers above the ground to drop off Brotherhood, quickly hop into it before it flys away. Fly over to mainland before quitting the mission or you will be warped back to where you start the mission. When you reach land, quit the mission. The helicopter is red with a gold strim and black tinted windows.

Brotherhood Boats and Jetskis - In the Brotherhood mission "Enemy of My Enemy" When the brotherhood start arriving, wait until they arrive in boats, get into any jetski or boat they arrive in, and drive over to mainland, then quit the mission. The boats are red with Brotherhood decals on them. And the jetskis are red with black or white stripes.

Samedi Chopper - In the samedi stronghold "Bavogian Plaza Drug Labs", bring a chopper over with you and start it. Progress through the stronghold, and when the samedi helicopter arrives and you have to destroy it, don't! Instead, get in your helicopter, fly above the samedi chopper, bail out and parachute onto the samedi helicopter. Press Y to enter the chopper and quit the mission. It is green with a silver trim.

Ultor Limo - In the last mission in the game, once Vogel goes into the ultor building and abandons his limo, drive to the ultor building, and his limo will be there for you to steal outside. Get into it and quit the mission. It is black with the Ultor logo written on each side.