Yeah, beware being insured for market value vs agreed value, especially if your car is in good condition, low kms etc.
I always play with the agreed value sliders, and for my car, it's little extra cost to have it insured for it's real value vs the 'average' market value.
Note also that the market value will usually continue to decline throughout the year. So, eg, using the example above, the market value might be $7500 now, but $6000 in another year.