The SeaArk my friend has is a bit smaller, but rides very well even in chop. It does not like 35mph winds and 4-5ft waves! However, I am sure that not many smaller aluminum boats would like those conditions. It is built like a proverbial tank. It is slightly heavy. I am willing to bet that the seating arrangement and size of the ZX180 would give you an even better ride.
I would say that the hull is good to go as long as the previous owner hasn't been aiming for channel markers, other boats, or large rocks. If the motor checks out alright and the trailer is good, I would say that 5000 would be a decent price.
As a side note, a mod V hull should do what you want. I've spent plenty of time on an 1860 Grizzly with a 60 Merc, a 1754 Lowe with a 50 johnson, a 1652 SeaArk with a 40 Tohatsu, and a few others. These all ride much better than a flatbottom. Pickwick can't get worse than Guntersville in winter, so you should be just fine with that SeaArk.