bridging channels on stereo reciever

[9am53]

cool, well the drivers are I belive 8 Ohm...but on the back of the reciever it says 4 to 16 ohm output...does that mean it adjusts to the speakers on its own, or should I go inside and change something...
Also...I am not and audiophile...but aspire to be one I feel that the receiver speaker combo I have sounds quite well, but really dont know. from what I understand the speakers are not the best...but I feel they sound good enough...is the reciever a weak link though? For good stereo sound should I consider replacing it, or is it good enough? I used to think solid state guitar amps sounded better...but forced myself to try tube ampsbecause those in the know claimed they were better, and now I totally see the light (so to speak), for HIFI solid state is beter right...ie better reproduction w/out distortion? or are tubes superior here as well? sorry about the random questions...but I like good sound, and I find its really kind of addicting!!!lol, thanks guys and gals