My plan has a cap of $1500 on the stereo. Fortunately the adjuster worked with me on it. My Z2 was over $1500, plus install, pus XM, Plus BlueTooth, Plus install kit, etc.
It is best to call and ask. Telling them you have $2500 or so into it should not increase the rate much.
I plan to do so as soon as I install a replacement. Mine was taken this weekend, after only three weeks in the car.