Cost is high.
Wow, I'm surprised at the cost for parts.
Anyway, the upper chain is relatively easy but the lower chain requires removal of the
transmission from the motor.
So, if you plan on pulling out the tranny yourself then do it yourself.
I have a feeling you could pay your local mechanic less to do this job but while your in there you
may want to think about clutch (or if lightened flywheel was ever something you wanted to do this
may be the time).
So it will end up costing you more just b/c it's so easy to say, "while my tranny is out I might
as well do -FILL IN THE BLANK".
Bottom line: it's expensive but worth it if you replace the guides too. No more chain chatter
(well, a little bit but much more quiet).
Let us know what you end up doing.