Sorry but anyone who think synthesis is what Saren is talking about has either never played ME1 or has never seen the synthesis ending. And no amount of memes will change what is clearly depicted and narrated (and confirmed by bioware) in the actual ending.
BTW if Saren is machine and flesh intertwined it disproves your assertion he was talking about synthesis, he was simply an organic with reaper implants.
I did both those things and... yeah, no, I'm pretty sure the Reapers are not only all about Synthesis, they are the product of it. The actual Synthesis ending just appears to be a more refined form of it.
You can stick your fingers in your ears and go "Lalalalala" all you want, but it doesn't change the fact that the Reapers are synthetics composed of organic parts, their MO has always been inter-meshing organics with cybernetics (look at any husk or the Collectors), their leader's idea of a wet dream is turning the whole galaxy glowey matrix green, and Saren was ultimately down with the idea of all this, even if what he went through wasn't as refined as what the Crucible does.
Also, saying that Synthesis isn't just filling everyone in the galaxy with Reaper implants is... well... you just can't say that. It very well could be. It isn't stated one way or the other, but... who knows? The implants might all be based on Reaper nanites.
Aaaaand that's all the thought I'm giving that for the day.