I wouldn't even consider something like this.  I might consider the
rustproofing alone if I lived in a rust belt area, but remember that you
can probably get this much cheaper elsewhere.

Hi,

I'm 3500 km and going strong!  I didn't get the dealer undercoating.
There's a place in town that does it cheaper, and I think perhaps better.  I
think that most dealers send it out to get it done anyway, so why bother?
I'm going to have it done before winter.

I love my Sedona.  Works great, good value!  It does get poor mileage, but I
knew that before buying it.  Although, there's a full steel frame, so you're
paying more for extra weight which means extra safety, IMHO.  Besides, we
saved a bunch up front, so we pay a bit more later one.

I did replace the Kumho 798's after 300 km.  Bought a new set of Michelin
Harmony (including the spare), and the difference is great!