(Sunpower story updated for Auriga downgrade, share slump)NEW YORK ( TheStreet) -- It was the best of times and the worst of times for SunPower ( SPWRA) shares on Monday and Tuesday. On Monday, SunPower shares surged by more than 8.8% after the U.S. solar company announced more 711 megawatts in projects sold to Southern California Edison, but projects years-out in terms of development and earnings impact. Then late on Monday, Auriga Securities downgraded SunPower to a sell and SunPower shares proceeded to give back half of Monday's gains, down between 3% and 4.5%, and reaching their average daily volume of shares before the midday mark on Tuesday. SunPower has been one of the most beaten-down stocks among the solar group, and therefore, any catalyst for the group as a whole that indicates a stronger 2011 than the bears would allow helps SunPower to rise from its 42% decline over the past year. That rally point for solar occurred on Monday, when LDK Solar ( LDK) upped its 2011 guidance, leading to big gains for many stocks in the solar sector.