Newbie Needs Help

I have a Bal Canto Evo 2i, a Cary 303/200 and JM Lab Chorus S speakers. I know my speakers are the weak link but I don't have the wallet for a substantial upgrade at this point in time.

I like the bass and mid that I get from the setup but the highs are a little too harsh and bright. I'm using a very old set of MIT 750 S3 speaker cables and stock power cords. I do not have a power conditioner.

Does anyone have any recommendations for cables or power options that may relieve the harshness that I'm getting from the top end, without adding to what I already think are quality mids and lows?

Thanks for any suggestions,
Scott