My left front absorber is leaking oil.I guess I have to change the front pair.Questions:1. What OEM or original BMW absorbers should I look for? I have read Sachs and Boge here.2. How much does it cost to replace them? I have read here that some change the cover, damper, mounting, link road as well. Is this necessary?3. How long does your front absorbers last? I have read 3-4 years and up to 9 years for some here.4. Does anyone have experience with M1 in Kayu Ara? I spoke to one of the mechanics, many of them there, didn't manage to speak with the supervisor or boss.Thanks!