To buy or not to buy - that is the question

Hi,
I'm new to this conference and have a question about 2001 Leganza - I've seen and tested it today and I'm in doubts.

The car has original 50kmiles, almost immaculate body (one dent and one scratch don't count), has been taken by Ford as a trade-in and then sold on an auction to a dealer. The problems I've seen there:

* the exaust pipe is not original and there is some loose connection near the muffler. The dealer told me that he has installed some generic rigid element instead of original flexible one

* I suspect that the transmission has been rebuilt since there is a liquid
seal instead the original one. May be Daewoo uses to make them this way but I doubt.

* There's some extra pressure under the oil lid - my 10 years old Chevy Lumina has a rebuilt engine with 145 kmiles (30kmiles after rebuild) and one can fearlessy open the oil lid.

* I scanned the codes - none of them is stored, but some of the sensors are not ready, either. The dealer says it's because the battery was disconnected and I can believe in that. But, on the other hand, the sensors are also not ready after the errors have been erased.

In general, the vehicle looks nice and is clean inside and outside but it is the least I worry about. I'd prefer to get a reliable engine and transmission.

The price is $3K - what is your opinion based on this information and your experience with this car?

Thanks