I'll give my "barely initiated" point of view -
The 2313 and 3313 have good auto calibration capabilities so I would buy the receiver and center channel, calibrate it, and see how it sounds. If you are unsatisfied or notice serious discrepancies between your center and L/R, then upgrade. The smarter members on here can probably give you an answer based on the crossovers, SPL, and a variety of other acronyms that I'm still learning, but it all comes down to whether or not you are happy with the sound.
I'm one of those budget home theatre guys (as my full EMPTek system will attest) so I would try the lower cost option (center only) first and only upgrade your L/R to match if you are unhappy with the sound.