150k KM does seem kind late to switch over. I would agrre that if it has worked for you so far don't change using regular oil. Something that you could is use this stuff called GUNK(thats the brand name). I am not sure if you have it up in the great white north. I have used it on my civic and my girlfriends dodge truck. What you do is it in before you change your oil. Then you run the car for five minutes and change your oil like normal. I swear to you when i changed both the car and the truck i had two different color oils come out. One was the this nasty dirty kind of black oil first, and then the normal oil after 3000or so miles color. Its a cleanser that helps get rid of all the natural oil byprducts that just build up in your engine and oil pan like varnishes and stuff. YOu should be able to find it any auto parts store.

thats just my 2 cents

ronin