Any advice on Head Units. I am sure this has been discussed here but not recently and I am looking for more current opinions. I am currently running the RCD-510 with 9w7 bluetooth. It works very well but is a bit dated (slow, clunky, black & white). I have read a lot of reviews on different units but most seem to end up going back to the stock unit or upgrading to the 510. I was looking at the Eonon unit or Joying as they seem to be the best for the money but again people complained espscially about the bluetooth. The stock unit is very reliable and the bluetooth works spot on so I am afraid I will be downgrading if I change it. Anyone have a RCN-315 installed? Thoughts?