"Sirius XM is cheap," I argued earlier this week, and at least one major analyst agrees with me.

Lazard Capital's Barton Crockett upgraded shares of Sirius XM Radio (Nasdaq: SIRI) -- from neutral to buy -- this morning. He set a price target of $2.25.

Crockett's bullish turn is based on improving fundamentals and upcoming catalysts that should double adjusted EBITDA to $1.5 billion in three years. He sees next year's price hike and a 2013 contract reset with General Motors (NYSE: GM) as primary catalysts in boosting profits and scaling subscriber acquisitions costs, respectively.

Crockett also expects CEO Mel Karmazin to commit a fair chunk of its healthy cash flow to share buybacks, ideally eating into the whopping 6.5 billion shares outstanding.

The stock was already having a good week after John Malone -- the head of Liberty Capital (Nasdaq: LCAPA) that owns a 40% stake in Sirius XM -- revealed that he would be eliminating Liberty's tracking stock. Combining Liberty Starz (Nasdaq: LSTZA) with Liberty Capital will give it an easier path for future acquisitions, though an actual buyout of Sirius XM -- though long speculated -- would be difficult.

Sirius XM's enterprise value of more than $14 billion limits the potential buyers. Even if one would argue that Liberty already owns 40% of the company -- and roughly a third of the enterprise value -- Malone will likely have to settle for smaller purchases if he goes that route.

Sirius XM's best growth will come as an independent, especially if it's able to realize Crockett's targets.

If you want to see how Sirius XM stands up to the stream teams, add Sirius XM Radio to My Watchlist.