A speaker's magnet weight or size has no bearing on the performance of the speaker. What does matter is the magnetic flux density and magnetic flux density linearity in the path of the voice coil.

When was the last time you bought an amplifier based on main transformer weight? Was your car purchase based on the length or weight of the engine? When was the last time you dated someone based on the size of their ... oops, nevermind on that last one.

Paul