Whats the best??

Double Din head unit for Sq Thanks in advance???

Panasonic Bottlehead

bar none, that is the best double din SQ headunit right there.

But I am guessing the OP isn't wanting a pure SQ headunit, since the majority of DD heads are DVD capable.

If that is the case, then I would suggest the Kenwood Excelon DNX9990HD

Triple 5.0V Pre-outs with Crossover System – Get the most out of your external power amplifiers by delivering a low impedance 5.0V high voltage audio signal to maximize sonic performance. Using the built-in crossover system, you can also easily filter out unwanted frequencies to your speakers and subwoofers to tune your system to its maximum potential.

Or you could look at the Pioneer: http://www.pioneerelectronics.com/PUSA/Car/DVD-Receivers/AVH-P8400BH

Thant depends what he wants it to do and what option he wants. If it is a pure sq build the Pani is the way to go. Other wise any of the Kenwoods. The 2013 models will be minty.