Also, on the head unit, what is there presently? Most of the US 2004's I've seen have the HVAC controls integrated. There are solutions, and many threads on here about it, but just suggestion to take some time to figure out what you want to do. I -really- like the USA SPEC BT45-TOY Bluetooth Phone, Music & AUX Input Kit if you find you can't easily change out the head unit. Sound and microphone are just fine. Mr Toyota took a dark turn in the early 2000's when they started integrating the HVAC with the entertainment system.