Oh boy, the opinions about Skywagons are as varied as Super Cubs.
Just to let you know where I am coming from on my opinion about 180's. I owned a brand new AC Scout before my 180. Things in life changed and as much as I LOVED the Scout, I had to sell it to buy the 180. I wanted a 4 seat plane that could do at least 90% of what a Scout could do with the same or better performance, loaded. So I spent 8 months searching for a 180. I was jaded with owning a new plane, only to go looking for a 50 year old used one. The good thing is that there is more stuff to modify a Skywagon than you can imagine, second only to Cubs. Many are good practical upgrades because of the age of the aircraft and past use.
I think most pilots who have flown all the 180 models will agree the early models are the best handling, like your 170. It just feeeeels right. As time went on they got heavier with minor changes that may or may not have made a big difference. Check this website out:
http://www.skywagons.com/modelchgsweb.html
I have a 1955 with a P-Ponk O-520 and I think it makes for the perfect personal plane. Its has enough mods on it to make it a hybrid, the best of the 180's and 185's with out the extra stuff I don't need. The gross weight is not has high as the newer ones but so what? I don't need to haul 1300lbs. It will still haul it though.

There is a saying about 180's, if you load it and can close the doors it will haul it.
The O-470 is a good reliable engine and if you watch your weight, a good performer in the 180. I would recommend that if you are even THINKING about overhauling the engine or upgrading you go with a O-520 and Mac 401 prop. P-Ponk does a fantastic job making them sewing machine smooth. The cost is only a couple grand more, but the performance increase in climb and cruise, including a 2000 hr. TBO compared to 1500 hr on a O-470, makes it worth it by far. Plus its still a simple, low compression, carbureted, big liter O-470. I think its the best compromise in cost vs gain. The 550 is ridiculously expensive for the additional gain, unless you are using it on floats, but if you have the $$$ you can justify anything.
Be careful when searching also, there is alot of junk out there. The planes history lends itself to getting beat up. My opinion, but if some one says they have a 180 with no damage history they are lieing or they lost the logs. Just be careful. My 180 does not have the logs before 1970, so what? I don't care about what happend to it 30 years ago. As long as the plane is straight, repaired correctly, corrosion free, and the current logs are in order that is what is important. A pre-buy by a Skywagon mechanic is very important. Does he know the correct tension of the control rigging? How about if its rigged straight in the wings, not with the trim tabs. These little details were things my mechanics found on mine. It can make a 10 mph speed difference!
If you want, you are welcome to fly a couple hours south to California and fly mine around. You can then decide for yourself what you might want or not want.
You will love it once you get one I am sure.
