Oil Leak - Not a normal oil consumption issue

I just got an 03 A4 1.8T from my mom. Unfortunately, she won't be a lot of help, as she's got early stage alzheimers, and isn't good with details. It had been burning a quart every month or so, so she took it to the shop. I'm not sure what they did, other than an oil change, but I just picked it up from the shop, and then drove it 300 miles. In that distance, we had to stop every 50-75 miles to add a quart of oil, because the low oil sensor would trigger.

I haven't yet had a chance to do much investigating, as it's been raining, and I picked it up sunday evening. It's my first 1.8T, so I need help with locating the likely suspects. I know she ran full synthetic, and had the oil changed regularly. I also know the engine was replaced in the last 10k miles or so (the body has 153k miles on it) from another A4 1.8T with similar miles. I don't have any service records from the last 2 years.