we are dealing with stereo ,2 channels. so 2 channel gets either of them. yes amp does have rca out which goes to sony monoblock. that sounds like hearsay. control in hu provides only comfort of control at finger distance. my idea of clean sound is shorter cabling and lesser controls. instead of bringing down all cables from HU i would choose 2 channel from HU and mix it or split it at terminations or amplifiers. 80hz filtered sound out of your head unit maynot be well in phase with the internal filters of subwoofer amplifier what will you do then? i know the ice installers will figure out something this or that to please your ears. i cannot imagine a reason why oem should sound so bad when the internal dac and other circuitry is almost same. i am wondering what kind of sonic inferiority are you experiencing from oem hu? to make it clear i will say oem flat eq does not sound flat to me . it sounds like ancient valve radio without proper bass and high presence from speaker out but it is a different thing at pre out level.. one which i ever found much better was a blaupunkt and an old sanyo player. and so called sony pioneer always sound bright to extreme bright to me even their loud speakers and subwoofers sounds crazy. neither of them sounded flat nor normal. whichever i have ever heard sounded with over emphasized treble and boomy bass . even in basic flat settings they sounded tweaked ,most of the time i had to use attenuator to bring it to normal level. yes the shopkeeper looked puzzled and stared at me as if looking at a fool when i said his expensive pioneer HU wasnt the kind of my taste. my taste of sound is clean sound .in home i have marantz sacd player and cambridge audio dvd player going through 7 channel power amps driving vifa peerless speakers and 15inchx2 jbl subwoofers. though oem head unit of punto cannot sound as good as my cambridge audio dvd player but it is not bad either. what i find unacceptable is integration of usb reader which is totaly wierd and not userfriendly.