Vanos seal replacement needed? M54B25
I'm getting the valve cover gasket replaced and was just reading up on it. Several sites mention that Vanos seals should be done at the same time.
From reading a bit about it, severe temperatures are a big contributor to vanos issues, and we're in a fairly temperate climate. I don't feel like there's any problems with torque or MPG, but it's mentioned that it's only after replacement that people feel the difference.
Is this necessary/advised (specifically for M54B25 with 170k miles and no sign of it being done previously)?
If so, what's needed/what costs/is it something a non-BMW specialist indy can handle?