NO, NO, and NO. Napa oil IS NOT rebranded Synpower. Additive packages are way different. Not even a watered down version of Synpower. BUT it is very close to the additive package of the conventional Valvoline oil. So it is basically a white bottle Valvoline oil with a slightly better base stocks, just enough to call it synthetic. Based on this - I will take SuperTech Synthetic ANY DAY over Napa Synthetic. Why? Because it is proven to go the distance with ease. Heck! even the conventional SuperTech oil was run out to 15k miles with a stellar UOA by "dnewton" on this forum! I have seen many SuperTech Synthetic UOAs that show same or better results overall against oils such as Castrol Edge, Mobil 1, and different boutique oils.
SuperTech is a VERY good oil, that is luckily available at such a low price. UOAs and testimonials on this forum back it up big time. You are more than welcome to use the search function through BITOG or Google.