ADS amp (old school)

I have a simple setup which comprise of CDT HD component, CDT 12'' sub, and a 4 channel soundstream vangogh 500.4...i'm running passive into the front comp and bridge the last two channel for sub... i'm thinking of buying the ADS PH30.2 which is a six channel, that's enable me to run front component active (75watts to mid and 75watts to tweeter), then bridge the remaining channel 5 & 6 to provide 300watts @ 4ohm to my sub... what i would like to know is, will this improve the quality on my current setup? or will the lacking power compare to the Vangogh shown here? but i've read lots of people saying power isn't everything, 75watts to efficient mid and tweeter is more than enough, and 300watts to my sub is just ideal since its rated at 300watts and 500watts peak... any suggestion? because i plan to go for active and i don't wish to run with two amps, that will require wire changes like power distribution block, 0ga wire, etc etc...what i want to achive is a more neutral sound system without sacrifying much power...PH30.2 fit the bill?

I say go for it.  The practical difference between 75w and 100w, especially in an active system, is next to nill.  I highly doubt you'd ever notice a difference.  The amplifier sounds like a perfect fit for your needs. New Project: 2003 Pathfinder

i've heard lots of people rave about "HEADROOM", since now my sub receive roughly 500watts resulted from the bridged channels of Vangogh, will the 300watts deliver by the ADS amp will not have those "HEADROOM"...???... and what if the 6channel driving all the channel all at once, will the power supply get stress till the sound quality affected as well? this is the thing that i really concern about...

Try the ADS out. I ran a ph15 which is 50x6, with the 642 csi to 4 sets of components, bridged the last two channels to a single ported 12". The amp worked perfectly. I was happy with the overall out put considering the amp is almost as old as me. the only word of caution is the older ADS amps are not particularly efficient, that is why they have those large heat fins on them. But again they are great sounding amps.