Piper is downgrading four solar names - LDK Solar (LDK -4.4%), Trina Solar (TSL -5%), Yingli (YGE -3.2%), and JA Solar (JASO -4.5%), while upgrading two others - Canadian Solar (CSIQ +1.4%) and SunPower (SPWR +0.2%). The downgrades relate to worries about pricing and margins, though LDK's high debt load is also discussed. The CSIQ and SPWR upgrades stem from optimism about the companies' project installation and U.S. residential ops, respectively.