What is the SACD Mod business all about?

I am interested in SACD and have been researching the many posts here on Audiogon. There is a lot of ink on these companies that offer mods to the basic SACD players. Some of the mods cost as much as the players. I guess I am bothered by the notion that I need to buy a SACD player then have it modded to get the best sound. Something just seems wrong with that picture. I mean do you buy a new CAT preamp and then send it off for mods. If the format has to be modded to sound good maybe I should just stick with cds. Any thoughts?