mazda9, I can't say for sure which company to use, but just a good tip, you only need gap insurance if you are going to stretch yourself thin on your loan i.e. your gonna be upside down on your loan. Basically for the duration of your loan, if at any time during the loan period you were to total your car, and the value of your car were to be less than what you still owed, gap coverage would cover the rest.
Gap coverage will NOT make up for your deductible. If your car is worth say 30, and the insurance values it at 30, less your 1500 dollar deductible, insurance pays you 30 + applicable taxes, less 1500, and gap will not pay for your deductible.
I just ran the NADA Valuation on my 08 CX-9 and clean retail is 26,525.
Had I bought my CX-9 new, I would have paid likely somewhere between 32 - 34k in 2008 plus taxes, and may or may not have rolled them into the loan.
That would mean I would only need gap coverage if now in 2012, 4 years later, I would have only paid down less than seven thousand or so, or less than 2k per year.
So again, you only need it if you are really stretching yourself thin making smallest possible payments per month.
As you can see, the cx-9 holds value well.