: While not exactly a service incident, I had a similar experience recently  
: when I bought a new truck.
: I had picked out the vehicle I wanted and after a little haggling we  
: agreed on a price. I wrote them a check for the down payment plus tax
: and license and told them I'd be back that evening to pick up the truck.  
: When I returned, I had to wait about an hour before the finance guy could  
: get to me. When I finally got in there, everything went smoothly until he  
: started adding up the numbers. He then discovered that they had  
: miscalculated the tax & license by about $150. He then said he needed  
: another $150 from me. I said we had already agreed on a price and it was  
: their problem, I wasn't giving them any more money. The finance guy then  

A similar thing happend to me a year ago.  I bought a used Ford Bronco
(which has since been stolen...  :(  )  and few weeks after I paid
and took delivery, they sent a letter telling me they goofed and 
miscalculated the license renewal by $300 and that I need to send
in a check to "avoid further delay" in the processing of my registration.
The thing is, I had already received the pink slip from the DMV, so
I ignored it.  I received another letter and then the phone calls
started coming.  First from the finance guy and then from the general
manager, both hounding me for the extra money.  They left me alone
once I told them I already had the paperwork and pointed out the clause
in the contract that stated that the final price was just that: FINAL.
Afterall, they wouldn't budge if I had told them I wanted another
$300 off after the deal had been signed, right?  I told them not 
to call again and that I would not do business with them in the future.
They didn't seem to have a problem with that.  This, after all, was a
used Ford at a Toyota dealership.

I had a much better experience buying a new Pathfinder about a month
ago.  It certainly pays to buy a car on the last Sunday of the month.
It was even raining too, so they had done very little business that 
weekend and were really willing to deal.  I kept telling them I would
think about it, and they kept dropping the price.  Got a very good
deal and so far have been very please with the service.