I picked up my 85 300SD in Vero Beach FL. Odometer stopped at 100,325 prior to 1995 - Carfax. Runs great, minmal blowby, No rust,only pass window doesn't work. AC even works! Owner died 6 mo ago only had maintenance records for past 5 years, which included regular valve adjustments. Drove back to Orlando @ 80mph rides nice, but accelerates like a turtle. This site is GREAT!

I paid $1600

Okay it accelerates like a turtle. You have to be more specific. What specis? Snapping turtles are faster than mud turtles for instance.
Actually doing a timed run to sixty would give you something to post.
Usually things like line or fitting blockage are typical. Tons in the archives as is probably the most common problem on 617 turbos.
Overall your car sounds like an excellent deal at this point. With minimal problems.

I was going to clean the banjo fitting this morning, line was off. Cleaned everything up, new hoses to alda. YEAH! now it has accellerates, kinda shocked me with second gear chirp (totally unintentional).

Currently at 9 lbs boost if accurate.

9.5 Lbs boost is the figure for US equipped cars.
Now adjust your valves, change filters, flush your brake system, check/replace pads if necessary and it'll be good to go!

__________________
Nate Stanley
(Currently Benzless)
1985 F-250 6.9l 170K
2009 SCION XB 36.5K
2003 LS430 78K
2012 Kubota B 2320