i've repaired hundreds of salvage cars and they can be a great value if properly repaired. i think 60 to 70 percent of a realistic retail dealer price is fair for a car correctly fixed, but sometimes that is not easy to determine. any half decent body shop can make the vehicle look pretty good on the outside but as TDI's are bought for their longevity whats under the paint, caulk, undercoat etc is pretty important, especially since you are looking at a newer car that could be on the road for many years yet. i have had various mechanics inspect rebuilt cars over the years and honestly i would not count on them to assess the quality of a collision repair. thats just not what they do. i once had a buyers mechanic call the state police on me because i offered a car for sale to his customer that had been "clipped" in the rear. where or how this was done was not evident to him upon inspection so he got it in his mind that the car must not have been legit. i had to remove some trim panels and point out some structural details to convince him that the car was repaired as i claimed. i have had other mechanics do cursory "inspections" for customers, mainly looking at stuff like suspension, brakes etc and completely overlook any structural issues.
you if you are going to shell out serious money it would be useful if a first rate body guy could examine the car, in addition to a mechanical inspection. by the way, did the seller tell you specifically what was repaired/replaced? does he have any photos of the car damaged?
on the subject of insurance, i have had numerous customers total their rebuilt cars, and every one was paid the normal payoff, no adjustment for salvage history. that is just my experience, but you can ask your insurance carrier, dont be suprised if they dont have a clear answer, but one thing is for sure, your rate for coverage wont be any different from a non-salvage vehicle..
all this being said, it sounds like the car could be a good deal for around 10k. just know that you wont be able to so easily sell/trade the car thus you should plan on keeping it for some time. and i would say that there are a lot of shyster/hackers out there cobbling together insurance salvage and you definitely dont want to get stuck with rebuilt junk so you better get the most disclosure from the seller and best inspection you can. ps if you have the vin i may be able to get some pics for you if the car was sold on one of the bigger salvage systems fairly recently.