Vice Versa
I have all mismatched. What was left of a home studio that got turned into my home theater left me with some oddball stuff that I did not want to part with. Sapphire SBs and very old DBx Soundfield Vs (one has had two drivers replaced, and the other has had three out of five drivers replaced) for fronts (If the wife is out of town, I'll move the Mirage Omni 7's in to replace the DBXs), Mirage Omni Center, Two Yamaha YST-SW315 subs, and six Yamaha NS10-MMT for Surrounds (SL, SR, RSL, RSR, PL, PR). It took a lot of testing and tweeking on my RX-V1400 to balance them (each pair is powered by a seperate Alesis RA-150/300 amp - another holdover from the studio).
You can do it, just be prepared for a lot of extra work in balancing the system. Not only am I using the RX-V1400 paramatric equalizer on all but the front channels, but two ART 351 graphic equalizers on the Mirage or DBX front speakers to make the system sound smooth.
As I said it will take a lot of work, but when I put in a Test tone CD, it sound the same in all speakers.