As markshan said, Klipsch speakers are about as bright as they come. Even with the Crites diaphragms installed, they still push the edge of what I'd consider tolerable for long listening sessions.
That being said, I think your best upgrade point at present would be speakers. Check around on CL and wherever else you wish and do some research on what you find.
Also, if you are local, check out the inventory at Vintage Hi Fi. You may find something there that you find tonally pleasant.