The alpine cda 9815-9813's are totally freakn nice.

I know that they are about 4 years old now, but the newer alpine stuff just isnt worth it now.
Is why I purchase these head units off of ebay on a regular for systems that I put in.

I have never had any problems with these hu since using them.

Sound quality is superb and can be used for sound pressure as well.
Specs are also great 60x4 and about 27 rms on each of the four speakers inside the car.
3 rca outs for highs n subs ect.
4 volts rca's as well
Tons of crossover to adjust
5 band eq.
Xm radio module with any input rca as well for ipod ect..
I do not use amps for the inside speakers due to the fact that this head unit has enough of power to push just about any tweeter to its max and just regular speakers as well.

The newer alpine head units are not as loud in any way as these generation of hu's, I also think the new head units are made with cheaper parts for alpine to get richer on.

Sorry for the small description, Im late for work.

Have to say,
These headunits rock my jock.

!!!5 stars !!!

Ill be 60 years old using this hu still.
-Doug in baltimore