Aktiv Cards for Ninka

I have a 2250 power amp and the AV 5103 System Controller, together with bi-wired Ninka Sprs -heavy granite stands. What are the requirements for Activ cards and how would these improve the sound? Speaker cable (8ft.pair) is LK400. Musical taste - primarily classical and occasional jazz. Speakers are positioned either side of a 34" TV, about 12" from the rear wall and approx 36" on the sides. Can the position be changed to advantage ? Thanks anyone.