When I got replacement parts from them in the past, they were just teensy plastic parts. They sent them for free, so I didn't complain about the shipping time. I think it took a couple weeks.
UV units are hardly critical pieces of equipment, so you shouldn't have much to worry about.
Yes, UV lamps lose efficiency just like any other fluorescent lamp. They should be replaced every 6 months or so, which is one of the key drawbacks to UV units... they cost a ton to maintain.