What's your complaint with your current radio or what feature are you looking to gain? Most are satisfied with the HK HU with an amp & good speakers, I said most not all.
One of my problems is CD's. Seems to always want to skip after awhile. Would like a an IPOD interface or thumb drive or hard drive of some type. Would like blue-tooth interface. Would like a bit better power and cleaner output from the unit. That is about it. There may be other benefits but I have not looked close enough yet.
Sony CDX-630 - Just installed recently with Hawg Wired kit which is easy as it gets. Front USB port is ideal for plugging in my Ipod for hours of endless tunes.
The best instructions I have gotten in a long while. The Harmon sounds great in my 05 Electra and works like a champ. I just have to run the wire for the AVC.
Thanks