I debated spending the big-bucks for a full GPS/audio unit, but bailed after a short discussion with my bank account; at $149 the DUZ3955AT seemed a good value, and I liked the fact it was Double-DIN same as my factory unit. The mounting instructions are limited to Toyota or Nissan vehicles - nothing particular for my GMC Sierra. I passed on the $30 install kit, and spent $2 for a scrap of clear plastic and some metal to make brackets and relocate the rear pin mount - the location provided is in the wrong place for a GM product. After some cutting, painting the back of the plastic makes a perfect factory-look face adapter. I also made a small 3/8" spring plate that adapted my GM antenna lead to the to-large socket provided by Clarion. I did purchase a GM to aftermarket system adapter - $40 Wal-Mart - required to retain GM signal controls on late model products. Warning - if you are not into a little handy work, a so-called 'free' installation could add $60 for the GM adapter, $30 for a faceplate kit, and $8 for the antenna adapter, totaling over $100 with tax, bringing the unit to around $250 or more. I did upgrade the factory speakers with a pair of Kickers and rear Altecs some time ago; I doubt if the factory units would handle the Clarion’s output or do the quality justice. A buyer could face a chunk of change to replace factory speakers – mine listed for well over $250, and I went whole-hog with sound mat and baffle boards. I was a bit surprised that the remote control unit was extra, but found a unit at Amazon for $7 - far less than the $30 MSRP. I was not overjoyed that it will cost $100 to add Sirius, but XM installs for around $50. In addition, Clarion requires two constant power circuits with the fuses insanely located on the pig-tails close the head unit. This makes the radio difficult to install, and requires removal of the unit just to change a fuse. I elected to add fuses to my under-hood fuse/relay box, since I had to run a #8 fused wire to power a future rear amp, I ran heavier gauge wires to the Clarion as well. I am generally pleased with the performance of the unit, but notice a slight tendency to 'flutter' or 'warble' at high volume with the extended low-range enabled, particularly when the unit is hot. I suspect the high current required for 'Z-Enhancement' is causing the output section to slightly overheat since there is no integrated cooling fan. I am not too concerned since I will install the additional amp next week that preclude using the extended low-end boost in the radio. I may add a heat-sink and fan to the output cooling plate later since I have room. The USB interface works great, with full control of all media I have tried, but I wish they would provide a panel mount for the connection cable provided. Since all my equipment can use a 5 volt USB connection to charge, I eventually will panel mount a row of connectors. Clarion states the unit is not compatible with USB hubs, something I will test out with several different units I have. I probably would purchase the same unit again, however, the very reasonable price can easily climb out-of-sight with a few additions or available accessories.