zaldek s2000's, ESS-SL50's

[soler]

hey im new to this forum and to advanced audio.
bought the zaldek 2000's left/right/center and a friend of mine gave me hes ESS SL-50'S for rear speakers
my receiver will be the yamaha rx v371
how are these? i havent found anything about the SL-50's but the guy the that gave me doesnt have shortage on money so i would think they are good, how is the combo in general, and may i point out, ive never owned a HT system, this would be my first but i still wanted to get something good thats not cheap and a waste of my time, i want a close theater experience and im hoping to get atleast half of it with this system. my friend who bought the wharfedale speakers told me they sound amazing.
would like to know more since i cant find much info online.
thanks.

oh and how important is a subwoofer for me?, my friend told me i dont really need one, does it really matter?