Many IAC rentals are 2 car/apt max. A good bet is to look for apartments with street parking available. Some experiences in no particular order:
San Paulo allowed us to rent an extra permit (3 total) when we were living there, but I was made to believe it was a one-off situation.
San Carlo has street parking, but good luck after 9/10 o'clock. If you're OK walking, you might be able to park across the street in the residential areas. All other spots are permit only.
Windwood Knoll has street parking. By extension, Windwood Glen does too but it's a slight walk. Both have non-permitted lots (Not sure now)
Estancia currently has open parking, but I'm not sure if that will be changing soon (they seem to be getting more strict with the parking situation).
Any apartment housing near UCI (Cornell Ct, Stanford Ct, etc) has horrible parking.
Don't even think about Park West even though they advertise street parking. Same with Turtle Rock Vista. I've had 3 friends' cars broken in to in these two complexes (2 Civic SI's stolen from Parkwest, 1 broken window/stolen radio from TRV)
Others to consider (I haven't had personal experience with these):
Newport North, Park Wood, Anacapa, Solana