180,000 miles on an '84 is only 7500 miles per year. Not bad considering the year round driving you can do with a 911 in California.
The big problem with this car is the fact that there could be motor and transmission rebuilds looming within 20,000 to 50,000 miles. The trans rebuild at even $3500 is worth it and almost expected maintenance at this stage of the game, but if you have to do a top end or a full motor rebuild, you better really like the car to spend that kind of cash on a 180k mile 911...
If you can spend $8000 to $10,000 on this car initially, dump $3000 into it fixing everything, you might just have a nice 911 that runs out nice and looks pretty good that might just last 5 years yet without big issues. However, all of these 911s are $20k car... Pay now or pay later...
There is definitely risk in this car, but even lower mile cars can run into big issues at this point in the game. Kinda gotta go with your gut on this one since you've seen the car and seem to have knowledge on what a good 911 feels like.
Good luck!
Jay
90 964, 84 3.2