security
all 2004 Prius come with remote
keyless entry. (you can unlock your
doors remotely with a fob as opposed
to at the door with a key).
all 2004 Prius come with an engine
immobilizer. (the car will not
start unless a recognized registered
keyfob is used to authenticate with
the car.)
Some 2004s come with an added anti-theft system
(factory alarm system). According to
http://www.toyota.com/vehicles/2004/prius/options.html ,
it is on the AG #4, AI #5, BC #9.
On the above listed Prius, you can
add the port/dealer installed
glass breakage sensor PPO V2, PN: 08586-47840, MSRP $149
On the Prius not equipped with the
factory anti-theft system, you can
add the port/dealer installed
RS3200 Security System Upgrade PPO V5,
PN: 08586-47840, MSRP $249
I'll note that on the classic
2001-2003 Prius, the keyless entry,
the engine immobilizer, and the
factory alarm were all standard, and
only the glass breakage sensor was
an added option.