Yesterday went into Strathfield car radio to discuss a wacky idea of creating a competition system for the XR6T. Talking to them, they dont know of a way to change the head unit or would want to as it controls air conditioning etc. You wouldnt really want to change it. Anyway they spoke of updating all the speakers in the car to the new pioneer speakers having 2 x 12" MTX Subwoofers and 2 x high powered MTX amplifiers, and creating a special subwoofer enclosure carpeted in the same carpet as the boot and up the level where it drops down (if you look inside your boot). They spoke about a custom perspex and wood box with the ford logo etched into the perspex and blue neon's lighting up the ford logo. Total price for upgrade $3500. Would be interesting to see what other places can do..or would be willing to do. They said though this would be an awesome system and would be competition grade. dont know how the head unit would handle it though..