SIRIUS XM Radio Inc. (NASDAQ: SIRI) now stands at a critical juncture, and this is a call which will not come about easily. It is time for a major change at SIRIUS XM, and that change needs to be the ouster of Mel Karmazin as CEO. The company just wrote off enough value from the XM merger that the current numbers are now almost numbing. Mr. Karmazin has been giving far fewer interviews and it seems that hehas been making far fewer public appearances lately. We noticed in oneof his recent interviews how Mr. Karmazin sounded far less confidentthan in past reports.