Thoughts, suggestions and comments needed for my planned system

My current system:
Pioneer DEH-P7650MP
Front Focal Polykevlar 136K
Rear Focal Co-axials 165HC
12"W6 JL Audio
Amp: U-Dimension JR 5.4x (5 Channels, 4x40w and 1x100w)

Planned system:
As above but replace the front splits and rear coax to Dynaudio 220MKII
Full sound deadening - G-SPOT Serenity Max
Headunit? (see below)
Amp? (see below)

Questions:
Will I be able to bridge the 4 channels to 2 for the dyn (dyn loves power doesn't it)??
And how much power will it produce if I bridge them?
Specs:
# 4/3/2 Channel Capable Power Amplifier
# 50 Watts RMS x 4ch at 4 Ohms
# 75 Watts RMS x 4ch at 2 Ohms
# 150 Watts RMS x 2ch at 4 Ohms

1. What is the best configuration for the amp I should be using for running the dyn and sub?

2. Do you think because I'm only using 1 amp, it will ruin my system?
I reckon u-dimension is pretty good and very clean amp..so I'm pretty happy with that...

3. Should I upgrade the amp? which I do not really intend to do for the moment...but recommendations would be good

3. Does headunit play an important role? what is the diffs with a good SQ hu?

thanks

an example of what is planned for my fronts...

ARC Audio 4150 XXK

4x80wrms 4ohms

2x320wrms bridged 4ohms is what will be running the fronts

always better to have more than not enough...

Your planned changes sound good. 150 RMS into the dyns will make them happy, and if you are only planning front stage and sub, this is how I would recommend you do it. I had a similar setup, but a bit more power and my dyns were great. If you were not wanting to upgrade the amp, then don't. See how this goes first.

As for the HU, while I am not too familiar with that unit, it should perform to the level you want and fit in with the quality of the rest of your gear.

your amp is very good. your choice of speaker are good too. HU is the weakest link here. it sounded very harsh. I have been using pioneer once and now I just can't accept the SQ of it. The only thing I ever come across from Pioneer which sounded good enough is the P9. very good actually. I don't understand why the make it like that but the gap between the normal line and the hiend line is too far. for your kind of budget ignore Pioneer in the next upgrade. there are something better for less $$$ in that section there. low end pioneer look good but the sound isn't good as it look

sorry just a stupid question but:

what makes a source unit play an important role in a system??
Does it make a hell of difference?

I have been told that pioneer is not a very good headunit for SQ..except for the P9...

What headunit should I consider for an upgrade? I like pioneer though...what about the 8450, 9450 or the new 9650?

there's nothing wrong with pioneers mainstream head units at all. i'd place them alongside their equiv alpines/clarions/jvcs etc any day.

the headunit is a fundamental component because its what creates your signal. the transport, dacs, filtering and opamps in the output stage all play a HUUUGE role in the final sound.

i.e. you've got a headie with 100db s/n ratio and amps with >110db, you'll be limited by your head unit.

while it has been said that the quality of your amplification and drivers is more important than that of your headunit, i tend to see things the other way.

garbage in garbage out and no matter how good your amps and speakers are, if your headunit sounds like ass, then your system will sound like ass.

also, in most instances, the difference in outright SQ through dacs/filtering/outputs only changes when you look towards upper/highest end products.

d