Thiel CS1.2 internal upgrades

Hi Thieliacs!  I have owned apair of 1.2’s for about 20 years, and while I really love them I am looking for a way to make them sound better.  I’m thinking that after 20 years there has been ways to improve on soundstage etc.  Has anyone had any luck with companies that are successful?
Of course another option is to upgrade to one of the “cs 2” series.  They seem to all get great reviews but if you have any personal experience I would love to hear good and bad experiences.  I currently run a Creek EVO integrated amp with 110 amps at 8 ohms.  Thank you very much for your help. Dave