Job well done! This is something I've been wanting to do since I got my TL, but I didn't have the cajones or skills to figure out the touchscreen and rgb interfaces. You nailed it and it looks great!
As I mentioned on acurazine, I hope to do a similar install this summer when I get some free time and money
BTW, how did you connect the audio? Also, did you consider remapping one of the stock buttons to flip to the carpc (eg. maybe double clicking the Map/Guide button).