Hi, in replacing the timing chain, etc., on the 420SEL which currently owns me, I keep encountering different brands of parts where I am ordering them (the parts section associated with this site). For example: they offer two different chain tensioners, with substantially different prices. As a hobbyist, I usually only do semi-serious maintenance like this once per task, so I have no idea if one is better or more desirable than the other. Can anyone comment on this? I need some advice without any desire to hurt anyone's business or feelings, as I try to support this site by ordering parts here. Thanks, and regards to everyone.