Maybe I am wrong (please correct me if I am), but the Crossfire manual and lubrication specs say to use an oil that is SAE 5W-30 or 10W-30? In fact, Pennzoil's website for their Platinum Synthetic even states:
• North American warranty requirements for U.S., European and Japanese cars and light trucks with gasoline and gasoline turbo-charged engines where API SM and earlier API categories are specified
• North American warranty requirements for U.S., European and Japanese cars and light trucks with diesel engines where API CF oils are specified (SAE 10W-30, SAE 5W-50 and SAE 15W-50)
• ILSAC GF-4Energy Conserving performance standard (SAE 0W-20, SAE 5W-20, SAE 5W-30 & SAE 10W-30)
• Meets the most advanced emissions and fuel economy standards in the US gasoline powered engines (SAE 0W-20, SE 5W-20, SAE 5W-30, SAE 10W-30)
• Meets Chrysler MS 6395Q (SAE 5W-20, SAE 5W-30, SAE 10W-30)
• Meets Ford WSS M2C930-A (SAE 5W-20) and WSS-M2C929-A (SAE 5W-30)
• Meets GM 6094M specification (SAE 5W-20, SAE 5W-30 and SAE 10W-30)
• Meets GM 4718M specification for Corvette and Cadillac (SAE 5W-30 and SAE 10W-30)
• Meets Acura HTO-06 for turbo-charged applications (SAE 5W-30)
• Meets demanding ACEA requirements (all grades)
Am I missing something?