I just messed around with my girlfriend's KDC-X693 and I love it. I played around with the time alignment and the graphic EQ that it's got. The graphic EQ isn't much, it's only a 5 band, but it suffices. The TA on it works pretty well. There are a lot of rumors out there that it only allows you to use the time alignment between front and rear. You do have full time alignment control after you select one of the preset listening positions. I selected the proper speaker sizes, or at least close to what her car has and set the crossovers as well. All in all, it was a rather quick tune. For the 15-20 minutes I spent in there, I'd say I would be more than happy if it were in my car. Also, RDS is a really nice feature.
By the way, her "system" consists of nothing more than the KDC-X693 and the factory speakers that a 2001 PT Cruiser has. It goes loud, stays clear, and is easy on the ears. I'd highly recommend this HU to anyone looking for a lower mid level HU with nice tuning features.
