Saab Forums - Saab Enthusiast Forum - Oil Light Keeps Blinking Off and On

I am looking at a 2001 Saab 95 with 115k miles from a private owner. I took it for a test drive the other day and it drove and handled like a dream on back roads. This owner has only owned it for 4k miles which is suspicious to me as to why he is selling it. The owner before him installed a rebuilt turbo and new Dunlop tires and brakes. This owner has put on a new exhaust system and had to have the #1 piston replaced.
After I took it out for a 10 mile drive, I noticed that the "oilcan" light on the instrument panel would blink on and off at idle. The owner tried to tell me that that was normal due to the high heat and humidity that day. That seemed like a very unlikely cause. The second issue is the "whining" sound of the turbo. He also said that a couple of his previous turbo Saab's had a high pitched sound to them and this sound was normal
I explained the above to a good friend of mine who was a foreign car mechanic for 35 years. He said that he would not recommend buying the car because he felt that there is an oil pressure issue with the engine. He said it could be a clogged oil screen or that the main bearing are just about shot. More than likely, the first owner did not change the oil enough or he/she used the wrong oil. The local mechanic who now works on this car for the current owner said that he could drop the pan and install new main bearings and that this would solve the problem. My friend said that the crankshaft needs to be removed and machined so that all surfaces are identical. He said you could put in the main bearings, but that the problem would eventually occur again because the crankshaft was not machined.
I would appreciate any thoughts forum members would have on these 2 issues. He is firm at $4000 for the car.