Oil Additives E64

HI all, just passing on some experience regards stopping smoking or reducing smoking due to valve stem oil seals leaks. The N52 engine is prone to hardening of the VSOS as the miles go on. Mine is a 2006 E64 (91K miles now) and I failed an MOT 2 years back due to excessive smoking. After some research I decided that the Liqui Moly 'Stop Smoke' additive product seemed to be the best so I started using it. Within 250 miles the smoking had stopped and there has been no return. Last 2 MOT's passed. Quite impressed with the additive and have continued to use it on each oil change. At some point I'll need to get the stem seals replaced for sure but for now at least the additive solution is working. Always interested in sharing other experience of such additives, may be different manufacturers etc etc.