wow!! 450.00 for that relay.. can buy them for around 100.00...takes a few minutes to replace..I really am saddened when stealerships rip off customers..It may or may not have been the relay.. they might have just "mistakenly" disturbed some wiring near the glow plug harness
To complete the repairs story: 2 days after I got the car back from the dealership from the glow plug relay replacement, the car wouldn't start. (Washington DC, not a cold morning.) I had to get to work, so I had roadside assistance come on Saturday morning about 10am (still not cold), and the person tried to jump it, first with a battery pack and then with both battery pack and cables to his car. He tried cranking it until I told him to stop when smoke started coming out of the engine and there was a distinct electrical burning smell. Just as part of the sob story, when the tow truck from roadside assistance finally arrived, the lift wasn't working so I had to wait for someone to come fix the tow truck.
In any case, the dealership said the battery was dead and replaced it ($260). Now the car starts, at least. I'm almost believing them that it's just a battery, as I think the prior battery also lasted about 4 years, and 4 years for a car battery doesn't sound that bad. Still, it's extremely annoying to bring a car in for a recall and end up spending $700+ on random repairs.
Back to the emissions modification: the car still smells like diesel exhaust inside when the windows are rolled up. I've been keeping the windows open because the smell makes me slightly dizzy. I had VW Customer Care contact the dealer's service center to do an investigation and I'm supposed to hear back about that next week. I separately contacted the TDI Settlement support number and the person there said that if Customer Care's diagnosis indicates that there is a problem, it is possible to switch to the buyback even after the recall work has been performed.
I'll post another update when I have more information.