[Piotrsko]

Depends on what caused the salvage title. Flooding is slow corrosion death to electronics, even after it is dried out. Definately destroys EV batteries. Change fluids on a pre OBD vehicle, dry everything out,and it's good to go. BTDT

Rip off the front bumper, don't hurt the rest of the car that's 10 years old and it can get salvage value necause that repair is worth more than the vehicles value and insurance companies don't care about your sentimentality.

2000 and later VW TDI have rust prone rear suspension in salted road climates such that the suspension components fall apart. Body and everything else is still good but you are still out a lot of dollars manufacturing a new rear end.
If you have a Cali rust free parts vehicle that was front damaged and have the time to swap good parts off you can make good money from selling the remaining parts car and repairing your rusted TDI. Anything wrong with such a salvaged TDI? Probably not.