I am looking to upgrade my Shaker 1000 head unit also. My main reason revolves around Sat Radio, as I live in the middle of no-where. I have looked into decently priced aftermarket options; the one Im leaning towards is the Kenwood DDX319, which is very similar to the DDX318 (link below) but is also Sat Radio ready. I weighed in Complexity of the unit (I dont want something so complex, I cant use easily on the road), Cost (dont want a dollar store bargain, nor will I spend more on my radio than my car insurance), and lastly if it looks good, is durable, and has the functions I wanted (Sat radio).
The issue I am running into with most aftermarket head units is although many of the 2 Din Decks I find attractive hover around the $400.00 - $500.00 range, the required "upgraded" 1000w Shaker wiring harness (so Ive been told by several places - not sure why) costs about 200.00, instead of the regular 30 - 40 bucks.
Pick the brains of the guys here, but in your down time head over to a car audio specific shop, and see whats out there. That should provide you with an opportunity to check out a few units hands on. At least the install for our S197 is real easy, and shouldnt take more than an hour. Kenwood DDX318 DVD Receiver
Hope this helped.