Which "tweeks" are more important

I would go with power then isolation/vibration control for speakers, amps, the components.

Quality power conditioner first. I suggest, however, plugging your power conditioner into a dedicated outlet.

If I can do it I guess its dedicated lines first.
Thank you all !!

It depends on many factors. AC Lines with AC filtering is a must for a natural sound especially from digital sources. But if you speakers were facing each other then I'd say get your speakers set up properly, etc.

You have already picked out cables and equipment without your AC being treated and that could change what cables and gear you use today. Most system don't have the basics down but will go out and compare cables, cords, and gear. I found it hard to tell some differences between some of these items before I had all of the other items prepard for a system.

So the following is what is needed just to get yourself at the starting line:

1 Dedicated lines with AC filtering - see my thread on caps
2 Equipment isolation, speaker spikes, etc.
3 Room treatment
4 speaker placement

Again, once this is all set up, then you can start to pick out all the rest.

Happy Listening

Oh yes I agree, I installed four dedicated-circuits when I built my listening-room addition, and by all means, it does make a difference over a single multi-use circuit. That being said, not everyone is able, or in the position to pay someone a good chunk of change to run additional circuits. At a minimum, that job almost always involves fishing walls, provided that they don't contain any fire-stops or insulation, or cutting into and refinishing drywall or plaster, which can easily turn in to a big messy job. On top of that you have to find a suitable route for the Romex to run back to your breaker panel, which may be a long and difficult distance away from your outlet location. If you can pull it off, then go for it. Sound wise, you won't be sorry.

That being said, I would look at taking the low-cost tweaking approach first and build from there. How much will a set of spikes for your speakers cost? Will it make a difference? Probably. A big difference? Who knows, but usually, no one tweak will make a huge difference like upgrading your pre-amp or power amp(s), though you may read otherwise; however, a combination of tweaks may add up to big difference though. Maybe you can put together a number of reasonable-cost tweaks that do add up to a big difference. Maybe one or more of those tweaks may be with some power conditioning of sorts. I personally prefer the sound of my system with the power amps plugged directly into the wall with no power conditioning, but again each power amp is on it own 20 amp circuit, and you may like it differently than I do. I do condition the digital side, the electronic crossover, and the like. But in any event, good cheap power-line tweak is to toss out your $1.00 contractor-grade wall outlet, and replace it with a decent, but not necessarily an extravagant, outlet receptacle such the 100% brass (no ferrous parts)Pass & Seymour 8200MRI or 8300MRI for about $20.00.

Now here is an important tweak that very few people do that does make a noticable difference. Order yourself a can of Deoxit and disassemble then spray the stuff on all of your connections. If you haven't done that lately, you'll like what you hear once you do.