What can I do about crappy service?

[Probedude]

I have heard that gasoline with high sulfur content will cause the stinky
cat smell - it is making hydrogen disulfide - rotten egg smell.

They may be an additive you can add to your gas to help clean out the cat,
but I do think you should try a different brand of gas for at least 2 tanks
to make sure.

As far as water in the trunk, it probably is not coming from the trunk and
does indeed check out okay if the dealer was only checking the trunk seal.

You see, there are good auto mechanics and great ones.  Good ones can follow
a book and repair something, the great ones have experience and know what
else to look for that might mimic a problem.