Underwood Hi Fi mods to Denon 2910

I own a Denon 2910 "universal" player which I have been using in my dedicated 2-channel music system for CD and SACD playback. I have read about (on this site)Underwood's mods to the 2910, which are said to greatly improve sound quality. Has anyone who owns this player had this modification done and was it worth the cost? My system consists of Maggie 3.5s, ARC LS3 preamp, Bryston 4BSST power amp and Linn Turntable. I would appreciate any feedback on this mod that anyone can provide. Thanks.
I am also thinking about doing this to my 3910 and am seeking information about this as well.