Ok thanks; but its the same "Class" of speaker regarding soundquality.... ?
Yes they are both X-Series speakers and use the same drivers. The Encore versions of both use the Peerless tweeter and M165 woofers.
I am Looking for a system that does not need a sub because the listening space of my room is only 10x12 feet 
The MTM plays deeper and has more midbass to midrange body than the SLS. While both will benefit from a sub, if you aren't going to use one, the MTM is the better choice.
btw. do you have the cabinetplans of the MTMs? Couldnt find them on Dannys page sadly
I do have plans for both of those. Danny has the plans, maybe he'll post links to them. Otherwise I can send them to you.
Mike