Go with a name you know and trust.. and just get all the features you want for it. Blue tooth.. usb etc. and yes the sound improvement is there, especially with the frequency pass through variables.

You can wire up from the new units speaker leads, or get one with 4v RCA output. There's plenty of threads on the install. Most common "error" is the blue amp turn on lead position in the adapter harness.

I just did a quick install for now, but intend to come back and break the wiring out at the amp inputs for a true 4 channel control. I did this on mine and the ability to front / rear fade is worth the extra time.

If you can't "deal" with a black faced stereo, you will have to go marine grade to get the silver, which works fine still. We put this unit in the corvette last summer and wife loves the ability to change button display colors, which you can match to the normal green of the dash lights. She leaves it in demo for the color rainbow.. Was a nice Christmas surprise for her..