I've found it better, at least for my situation, to be a few feet further back then my 80's are apart, or even my 60's when I had them. They are about 11ft apart, and I sit back about 13ft for the main seat, however, the sound is even great for the rear seats as well.

I would not spend to much time dwelling on be exact.

I tried and I found that the equilateral recipe works best in my room.

Another question, while forming the triangle, do you guys angled the speakers towards you, or keep them straight paralell from each other???

I got today the M80 and I feel that I'm missing something, in comparison to my M3ti, I know that has to be placement related, otherwise it makes no sense, but what else to do????

The speakers would be angled in slightly to form the triangle.
What would help to know is how far spread apart your speakers are , how far is the main listening position from the mains, and what's the distance from the back and side wall for both the left and right M80's

I tried toed in, toed out, straight...you name it. For the longest time I had them toed them in with extreme prejudice and they sounded crisp and clear. Then one day I took them into a local audio store for comparison to Paradigms and when I set them back down in my A/V room, I didn't toe them in. They sounded more natural so that's the way I've kept them.

Make sure the straps across the back are in place properly and that they are in phase.

I second that one. I had one that wasn't in right when I first received them.

Well the position is a bit critical given that I have no much space to play with. They are 8 feet apart, and I'm 8 feet from them, the are like 12 inches from the back wall, I can make the distance bigger but then I have to reduce the distance from my seat to them, and thus reduce the distance between them...

My main problem is that I'm used to the speakers to be higher as my M3ti were on top of a 36 inches stands, so I'm used to an ear level was higher than where it is now...Maybe I need to get used to the new configuration...

If you enjoyed the sound of your M3s higher why not just raise your M80s up on blocks of wood. If that's what makes the difference I wouldn't hesitate to do it.

What exactly do you find different between the M3s and M80s with respect to height?

There is only a few inches in height difference from the M3 on 36" stand to the M80s. I doubt that is the problem. Have you checked the binding straps on the back of each M80 are they both flush to the bind post?

And lastly there is quite a difference from the M3 to the M80s, the M80s are much more forward sounding than the M3s, can you desrcibe what the differences are that you are hearing?