Yeah, if you are going to install a tensioner, I would definitely replace the chains too while it is apart.

Now, about the guides and rails, it is my understanding that replacement requires MUCH more labor, as you have to "dig deeper" into the front of the engine.


I received a quote of $500 for chain/tensioner replacement, but it went to $1200 when I asked about guides & rails. Unacceptable.

Good luck!