I have a stash of BC (14.3 cSt at 100C as best as I can determine). I have a new, under warrenty, vehicle that recommends only 5W30. I have ordered some 0W5 Racing oil from Redline. I am thinking about cutting the BC with the Redline such that the viscostiy at 100C is around 12 cSt. With the 0W5, that requires only a 10% dilution of the BC. So, the add-pack in the BC will not be off by more than about 10% for the BC components (yes, I do know that there are some errors in that logic). In addition, I am assuming that 90% of the detergent/buffer package of the BC is "enough" given that the racing oil is not likely to be robust in TBN and 'cleaning'. OK. Talk me out of this. What is wrong with this strategy. My plan is get both a VOA and a 4000 mile UOA (leaving the oil in until the results are know). Since I have some noise issues when the engine is cold in the winter, I am thinking about doing a similar thing to my GC stash for the winter. I do recognize that the GC is probably perfect for summer, but I am trying to get good use from the BC.