Spektrum receiver range comparison
 

Is there anyone who could tell me that AR610 or AR6270T has better range (in case of balsa fuselage)?

Are you looking for RSSI? That is found only in SPM4649T at this time.

Both receivers are full range. The AR610 does not support a remote receiver, but it has an amplified antenna. The remote receiver does not increase range, but it does decrease the possibility of the antennas being shadowed, and it can allow you to have different orientations (polarizations) which may give you a range increase.

But the receiver sensitivity is the same.

Andy