ZPM, this is the one to get (from a USA reseller): Pioneer DEH-80PRS
There are newer units on the market, but if your primary concern is sound quality, stop searching because this is the one. (Take a look at the reviews on that site if you don't believe me.)
The 80PRS has an SD card slot, though typically I use the Bluetooth connection to the phone for convenience of loading new music, building playlists, etc.
For the integration kit, I have an Axxess BX-GM3 which provides the connectors and handles the chimes with its own internal speaker. I'm not using the amplifier in the 80PRS (in fact you can disable it completely to reduce signal noise) and I soldered RCA connectors onto the "speaker" connections on the harness and then connected them to the 5V preamp outputs on the Pioneer for a direct preamp connection all the way through. You'll need to get the RCA pigtails separately. The interface box doesn't get in between the HU and the amplifier at all.
I just took a quick look at the Axxess site and it looks like the BX-GM3 has been discontinued and replaced with the AX-GMLAN11...which seems to be functionally the same thing. You basically need it to keep your chimes, your retained accessory power, and to give you a handy wiring harness and connector to make installation easy. You'll also need the ASWC-1 if you want your steering wheel controls to work.
I will get some photos of the settings on my 80PRS next time I'm in the car. I don't have mine setup for mega bass, but it's easy to dial it in to the point where it's unbearable if that's what you're into.
Looking forward to hearing how it goes for you...you won't be disappointed!