In need of some Amplifier advice. Is therereally any point in it with my current setup?

Hello. I have posted in the past, but have since learned a little bit more from reading audio forums, and doing some research and have come to somewhat of a juncture. 

I figure I could "stair step" up on my own and enjoy the ride, or, ask those who have most likely been where i am before and skip a few steps =). 

My current setup consists of a Yamaha adventage-A3070 AV receiver (150wattsx8ohms 2chd), and 2 Polk LSIM707 towers. 

I've been looking at used Classe amps here on audiogon, or possibly a new parasound Halo A21 power aplifier,  and have thought about purchasing them. 

My question is, would my Yamaha advantage 3070 even be a sufficient pre-amp? It has pre-outs for all channels, and it also has an ess sabre DAC for my digital flac files. Or would using the Yamaha as a pre completely destroy the sound of the power amplifier? Essentially wasting $1,000-$3,000. 

My other question is pretty obvious. Should I trade up, just spend the $1,000-$3,000 on better set of speakers I've been eye balling like  the EMT-LFT8s, and stick with the Yamaha receiver's power for now. 

If it were you. What would you do? 

If you really wanted an integrated, I would look at the Hegel. Like this H160:

It is pretty much the equivalent of the Parasound Integrated (but without phono preamp and sub crossover). Hegel also has limited analog inputs (1 rca, 1 XLR, 1 ht bypass). However I think the Built DAC is much better. The Parasound Integrated/P5 DAC is pretty much junk. I think it would be a better end result than the Parasound Integrated. There are more expensive integrated, of course.

The Hegel will be very nice, but personally I would rather go with A21 amp and a very nice preamp.

Here is the thing... if you try to upgrade your overall sound by getting better speakers and powering them with the Yamaha, they aren’t going to sound very good. If instead you upgrade to the Halo, you get an immediate improvement and can upgrade the preamp/dac later. 

And now the sweetner... if you buy the Halo preowned and decide a year from now to go a different direction, you will probably loose less than $150 on the resale as parasound halo holds its value!!
That was one of the reasons I was learning towards Parasound Halo as a whole. They seem to hold their value and are U.S. based making any problems easier to deal with. 

I was considering the A21 before I looked into an integrated. The Specifications seemed great for the price point and the reviews were all top notch. 

I agree with you on the speakers. As I've been playing with the various integrateds I mentioned what I thought were weakness in the speakers had nothing to do with the speakers. 

The integrated Parasound and Rotel boosted the mid range and bass response that seemed a little weak before on the Yamaha AVR as a lone paired component. 

At the moment i have the budget to replace all components if I choose to do so. So I am also looking at various speakers. 

However, I definitely agree with you after pairing my speakers with various integrated amplifiers that the source, (amplification) is the most important. 
And let me add Pre/DAC to the most important as well. The ground as you would say.