Peter, if by "bigger" you're referring to wide dispersion, the W T/M W design of the VP-160 is superior in that respect. If you're referring to the very loudest sound level, the VP-180 would have a slightly higher maximum, but keep in mind that the center speaker should be calibrated to balance the others, not play louder. If the VP-160 already does this, more maximum loudness capability isn't a relevant factor.

-----------------------------------

Enjoy the music, not the equipment.