I am currently using AR-315HO speakers with 15 " subwoofer powered by 500w amp built in. This is the model equivalent to the current AR-1 speakers. I am wondering if anyone is using SVS subwoofer with this combination. I just want to know if it makes a significant improvement. As I am in Canada, I want to be sure it makes a difference even with these speakers which have decent subs built in, before I import them . Any comments would be appreciated. Thanks in advance.