Just curious who has used Redline in a GDI engine long term and whether you've inspected the valves? Oil is chemistry and chemistry can be complex. There are different approaches for different engines and needs. Redline's stance on LSPI is that they don't have issues with it with their high performance RL chemistry due to the esters and higher levels of moly which help fight LSPI. Oils like Driven formulated a DI line which is mPAO/III/POE and has a lot of moly, but they dropped the high levels of Ca and replaced with Mg. Amsoil is more secretive and is likely using PAO/V (some have suggested 10-15% POE) but is also using a modern Mg/Ca combo.