The factory speakers designed for the Illusion Tower are very low-end sound wise. I believe that they utilize Sony components.
Skylon makes two better alternatives and will add a third one within a few weeks. The Skylon Illusion X Deafcon I uses 6 inch Kicker components that sound and look better than the Malibu Illusion X speakers.
You can move up one level to the Skylon Illusion X Deafcon II which uses 6.5 inch Image Dynamics components. You can even use two pairs. Each enclosure can handle 150 watts RMS (600 watts RMS for two pairs) and will really sound great. http://www.wakeside.com/page/W/PROD/skylon_wakeboard_tower_speakers/skylon_illusion_x_deafcon_ii
In a few weeks, Skylon will introduce the Skylon Illusion X Deafcon IV which includes 8 inch Image Dynamics mid-bass drivers and HLCD (horns). This will be the ultimate Illusion X solution for the 2005 season.
Check with Wakeside.com for availability information. We have a couple of audio experts that can help you with all of your boat questions.