If you set up the bushings according to the angles elephant and other specify as "correct" the arm isn't at full droop, its almost horizontal. (angled downward just a hair)
I'm not saying they don't last, I'm saying there is better options for the time, effort, and money.
It's $60 for a set of rubber units and about 1-2 hours or killing yourself getting them back on "correctly"
It's $75 for a set of Powerflex units and about 10 minutes to put them on.
As for lubrication, yes about every 30k miles you'll have to apply some new PTFE based grease
Yes, I talk up the Powerflex units, why you ask? (No I don't work for them )
They last almost forever / I've never had a failure
They out perform any rubber bushings and don't squeak
They don't smash from road impacts like Delrin or Bronze liners
They Fit well on every car I've ever used them on (Porsche, Mini, Subaru, Toyota, Honda)
There is almost no perceptible difference in NVH in the car after install, in fact sometimes it lessens it. (binding / twisted rubber units transmit more NVH by nature)
If you're interested you can find them
HereAnd you can do your own homework to see if they are up to your standards.
I keep badgering them to make a 914 rear trailing arm bushings but right now the Daystar Polygraphite (sold by AA and others) units are the best I can find.