Take a look at the MSB universal transport and Analog DAC. Several times the Oppo's cost, but you can play any kind of disc and the sound will be better than stock Oppo. There are also any number of Oppo modders out there, Modwright and The Upgrade Company both got Postive Feedback Online Brutus Awards
OPPO 105; how to beat it and at what price?
I am in the process of building my reference system around my new Wilson Alexia’s. I am currently using the OPPO 105. How much would I have to spend to get a significant audible improvement? What would that unit be?