You probably would need to ditch the HL speaker and the trimpot and replace with at least an FRS8-8 and 22k ohm pot, respectively, to make better use of Clark's board. Then you may go the Tamiya speaker route after both upgrades. For the capability the Clark board brings, its worth the value for money. If still left wanting, add in a Benedini and your set for life.
Me am settled with this routem watch in FULL HD (1080P) and FULL BASS ON ---->
http://www.youtube.com/watch?v=JZCiutJ1-js
http://www.youtube.com/watch?v=vFgKO9pqL34
http://www.youtube.com/watch?v=AQJzDV_39-w
http://www.youtube.com/watch?v=gYAUWoz0-Kg
hope you'll find your liking =)