I went to the hassle of fitting a hi line system to my old ZT. It was a massive ache and to be honest a pretty antiquated system. I bought a A-sure head unit from ebay for my next ZT and the head unit looks very similar the the original hi line system plus the sound was far superior. You can easily add a digi box plus it plays DVDs with surround sound.
If your still mad on fitting the system you will need all the loom and the brackets plus the rear window elements are different on a Hi line car and is used as the aerial for the sat nav.
