Engine mounts & 90k mile service

I recently had a left front CV boot replaced by NTB. They say it will rip again if I don't have the engine mounts replaced. Dealer quoted me betw/ $100-$300 for the various mounts. They are/would have been covered under my warranty which expired the day I brought it to the Dealer, but Dealer said they don't need to be replaced, & thus didn't replace. Service stations quoted me around $80/mount, so now I'm wondering what a reasonable cost is for these mounts on a 1995 automatic Maxima, and how can you tell if they need to be replaced? How many are there, are they "electric" as is referenced in the 2000 model yr specs?

Also, in the 90k mile service - is there anything the dealer can do (setting the engine specs) that a service station can't do?