OK HATE admitting this, but my engine has used/burnt 1+ qt of Amsoil 10w40 European formula (for e36 M3) oil! . Then I noticed SMOKE, and LOTS of it! SO after reading lots of posts, and the POwner said (and showed evidence of oil and other servicing), I'm thinking Valve seals... The motor has great power, (esp after my cooling mod! hehe j/k ; after changing to Amsoil, it was fine. SO, what valve seals last longest (I have 169,000 miles on it now). Put LOTS of miles on my vehicles! Just redid front shocks, suspension, and disc brakes! MUCH better! So, do the crappy valve seals cause all this BS? Thanks!Tommy