If the detector is in very good shape, that's probably an OK price for a Tom tuned 11.7" cz-3d with two coils.
Regardless of whether the seller says firm, I'd offer less. Especially if it's been for sale for a while.
Some people are fond of the cz 5" coil, but I have no use for one. If I'm detecting in a heavier trash/iron location where a small coil is appropriate I won't be using a cz.
Another good thing to know is that according to Tom Dankowski, it's common for the impedance on the 5" cz coils to be out of spec, making IDing inaccurate. Your detector was tuned to the 8" coil so it should be fine but since Tom didn't check the 5", it may not be.
The problem with buying a new cz-3d is they are less likely to be "hot" than the older 1021s. You might get lucky and get a hot one, and you might not.
If you get one that only gets 9-10" you're either going to be using an inferior detector or reselling and taking a good size loss.
Anyway, good luck with whatever you decide. When used in an area that's not too trashy, a cz-3d operating at "design intent" is a beautiful machine.
