I've had a toyota highlander hybrid for just two months now. I've managed to "upgrade" it in several ways, which I'll detail in separate posts. The most dramatic of course was adding a commercial quality BASS shaker, and high power amplifier (which in the end required me to take at least half the car apart, since I insisted it not extend into the cargo area)... I've also "calibrated" the A/V system, and installed the VAIStech SLI., which lets you watch DVDs up front and of course, play a reasonably large collection of music, controlled by the internal NAV system. I'm currently building in a "plug-in" power system, to recharge the battery when I'm parked at home.
I've photographed my extensive mods, so I plan to upload pics, for anybody interested in whats "underneath" all that plastic. Believe me, there is a lot- i've never seen so much krap stuffed into so small a place as the HH, making any mod ALWAYS a challenge.