Advice on the purchase of 87 300TD

[JeremyPDX]

First off - I have spent HOURS this past week on this forum educating myself and what a great resource! This place will come in handy on my "in the process" restoration of my 64 220Sb!
On another note, I am looking at a 87 300td and I wanted to take a quick poll and find out if: A) I'm crazy! B)I'm nuts or C)???

Found this car with just shy of 100K miles on the odometer, runs smooth with no smoke, great interior, tires, paint, etc. Supposedly, the current owner is the 3rd owner and bought it for his wife not long ago and she doesn't like its lack of blistering performance. Besides the "good" that I just listed the car has a few "bads": NO service history, sunroof problems, rear left window doesn't work, drives outside mirror is non-adjustable, a few rust bubbles on the rearmost vertical side window trim, A/C works but blows kinda cool, trip-meter is not working, the OAT display is blacked out, and the car feels painfully sluggish and doesn't overheat!
Before I went to look at the car, I studied up on the W124 buying guide and used its info to look over the car. I started the car cold and it fired right up and instantly set down to a smooth and quiet idle with no smoke. The car doesn't seem to want to move until the acc pedal is nearly 50% depressed - probably ALDA issues I assume. Once going it shifts hard from 1-2 and then holds 3k+ rpms before hitting 3rd and then is eventually smooth into 4th. The hard shift from 1-2 may have been because I was flooring it during the whole test drive?!

The car doesn't seem to have any leaks and the underside appears dry and rust free. With the lack of service records and my knowledge of cars, it appears that the engine is bone stock. Stock head, radiator, fan clutch, waterpump, injectors, etc. so my conclusion is that in the near future, things may begin to line up for replacement and repair. I work on my own cars and drive a diesel 1997 Passat and so I cannot forsee ever having to pay someone else for reapirs so I only need to worry about the cost of parts. The repairs don't intimidate me but his asking price does.... $13,500!

So, one of my first questions: With a lack of records and a broken trip meter, how reliable is the odo's mileage of 99K? BTW - I did witness the odo working while on the short test drive. Secondly - Is there a consensus on when low mileage overrides a lack of service records and would therefore justify the high price? I have looked around at a lot of these for sale on-line and the only one that comes close to this price is a nice example at a dealership in the Seattle area for around $16K but they have reciepts that total over $33k in repairs!

Should I offer the guy $7-8K, and make the case that without service records and the current issues on the car, necessary repairs will/could be in the $1000's? Should I keep looking - this is the car that my wife and I want for our lifestyle and big dog! OR what would a best case scenario car with low miles really be worth....?

BTW - this guy is a one-man dealer that specializes in vintage US and Euro cars so that also may account for a bit of the high price.

I really look forward to hearing back from you all and thanks in advance for your input.

P.S. I know that there may be a desire to send me running as a unsuspecting NOOB who doesn't know what he is getting himself into, but please refrain from that assumption. I am aware of the potential $$'s and ups/downs of owning one of these cars and I am willing to spend some $$ if needed if the right example comes along. Thanks again - Jeremy