Modding CDP's

I'm looking to upgrade my SACD/CD source for a little less harsh sound on old CD's and have been looking at the Marantz SA-11 and noticed the Underwood HiFi modded unit. They state the sound is a tad warmer and more tube like. That might me just what I'm looking for, but I'm confused as to how upgrading components would warm a unit. My first thought is wondering if they are simply dumbing down the sound which gives an apparent tube roundness, but probably yields poor measured performance. Any opinions? And that of course begs the question, is modding a high end treak or just a way to enhance a budget box? FYI I'm currently using the Marantz DV8400, MacC200, Classe monoblocks, wireworld eclipse. I know the conventional wisdom around here is to go with a tube preamp, but my system is on a lot and I don't want to worry about tube life and sound. Thanks