I have 4 surround speakers, the sides are TSi200's and the backs are TSi100's and i use speaker brackets that require one screw into the side of each. I did not use the screws that came with the brackets becasue i thought they were to large (diameter) i used smaller screws that would only dig into the would about 1/4". it's really to help hold it in place given the weight of the speaker. I also used black screws so you wouldn't really even know it's there. Also, given the weight of these speakers, you really do want them secured properly. All mounts like that for speakers will tell you that if you add any tilt to the speakers you will need to use the screw. this line is put in as a disclaimer so you don't sue them after your speaker comes loose from vibration and falls and clunks you on the brain! Obviously you don't want to drive 4" screws into the speakers! 1/4 to 1/2" won't in any way hurt the speaker or the cabinet. here are the brackets I use to hold those big boys in place; again, the speakers are heavy so don't use anything cheap and YES, use screws, small ones but screws non the less! These stands are the best for big speakers like the TSi200's; they are solidly built too, steel, not plastic. imo!
I have the TSi's on display in my gallery if you want to get an idea of what the brackets will look like in use.
http://www.bracketsandstands.com/BT_...ETS_p/bt77.htm