Took me about 15 minutes. Most time was spent cleaning the rubber confetti out of the groove, since my old one had turned to dust.
There's another thread
right here where peeps are fretting over goop to hold it in. I'm 90% certain there's no goop required. There was no goop on mine when I took it out and I didn't use any to put the new one in.
Once you have it out you realize it "seals" little or nothing. It's mostly cosmetic.