I've searched and read through various threads but need some clarification. I'm looking to replace my stock Mark Levinson (non nav) head unit in a 2001 Lexus LX 470. I have the new head unit, a Pioneer AVH-2600BT, and the plastic surround. I'm not aware of any wiring harness that is available and Crutchfield said they haven't researched the vehicle. I've done some head unit installs, but would consider myself a novice. To install this, do I just follow the wiring info I found here and connect it to the corresponding connections on the new head unit? I'll be keeping the existing amp and speakers for now.