You really should consider matching at least your front 3. You will never get a "good" soundstage or imaging without 3 matching. Rears are not as important.
Most receivers/amps can easily handle 6 ohm/8 ohm mixes. However, check your manual to make sure that your receiver can handle five 6 ohm speakers (since that will be a minimum rating to be safe).
Don't forget a good sub!
Most receivers/amps can easily handle 6 ohm/8 ohm mixes. However, check your manual to make sure that your receiver can handle five 6 ohm speakers (since that will be a minimum rating to be safe).
Don't forget a good sub!