I have a '13 Passat TDi That I just bought a few months back, we love it so far but all of the forums and such show so many having problems with the DEF system, the HPFP, the DPF clogging etc, its scary. I have a CPO as it was a dieselgate buyback car with 40k miles. so once my warranty is up I'm nervous but its been great so far and even just short tripping it we average close to 40mpg.
I too had a hard time finding 507 approved oils, and I hate mail ordering oil! I finally found some M1 at the local NAPA on sale for $5.99/qt so I stocked up, sadly I hate Mobil oils though

I honestly think ANY diesel spec'd oil with low SAPS will be fine in these. Many just refuse to pay the fees to test for VAG approvals. Heck, my car has Rotella T6 in it now since I couldn't find the proper stuff initially.