Question about surround speakers

acsubie

i am currently using Polk HTIB (cheapers set) speakers for my surrounf and rear speakers in a 7.1 system...front are currently Monitor 50 and cents is a CS2..i purchased some R150s to upgrade the rears, i can get a good deal on RM 7400s that i can use for the fronts, my question is would the monitor 50s be ideal for surrounds? or am i better off returning them and getting store credit? or even better should i just stick with the monitor 50s up front and just try and score some FXi4s for the surround

any input would be greatly appreciated