A:Answer Hello. Thank you for your question and your interest in our products. For the Motion 30i, we typically recommend amplifier power between 20-200 watts per channel. As for the speakers, the Motion 30i and 50XTi are designed with a 2.5 way crossover to prevent lobing from occurring below the tweeter crossover point. Unless there is a single driver that plays all frequencies, there will always be some lobing. The 2.5 way design minimizes this as much as possible. In a 2.5 way MTM (Midrange/Tweeter/Midrange) configuration (Like the Motion 30i/50XTi) both woofers play the same up to the lower crossover point, then one woofer rolls off, and the other plays up to the tweeter crossover point. This minimizes lobing effects, in the same manner, as a TM (Tweeter/Mid like 15i or 35XTi) design would. With this, combined with the controlled dispersion of the Folded Motion Tweeter, we are able to avoid these acoustic issues. We hope this helps and we greatly appreciate your support.