I know that this topic has been beaten to death but I find it really frustrating that it all depends on the dealer you contact on the informaton you're given about fouling plugs in the Gade 600 HO SDI. I just purchased an 05 and unfortunately didn't know about this fouling problem until after the fact. Should have done more research I guess. But anyway's, I put about 80 miles on the machine over the weekend and fouled a set of plugs. I was told by my dealer not to worry that it could be a result of the fogging and the end of the season. These plugs were BR9EYA. I replaced them with BR9ECS as per manual. My machine also has full synthetic according to the previous owner but was told by my dealer to use semi-synthetic. That being said, I contacted another dealer and they told me to use synthetic. I know that alot of the members on this site have been thru this before so I was wondering if they could summarize what I should be using in my machine? One thing to note is that I was also told by my dealer that they won't do the update unless I foul alot of plugs and I try the semi-synthetic with BR9ECS or BR9EYA. BR8ECS apparently don't make a difference unless you have the update. Any help would be appriciated!!!! Thanks!