You can wreck it getting it out. You can put the pole and shelves together inside the cabinet. It takes three hands, a small exclusive vocabulary and patience. You will need to know what size circle will fit in the hole. The height of the cabinet opening will dictate what size lazy susan will fit through it. If you are planning the pie shaped shelves you have a bit more leeway. OR You could put a shelf in there and set two lazy susans on them. You'll have to put each piece in and lay it on the floor of the cabinet in the order you will put it together. On the floor place one lazy susan. On top of that lay one shelf or if the shelf is in two pieces but both of them on top of the lazy susan. Then put the last lazy susan on top of the pile. Leave the bottom lazy susan on the bottom floor/shelf. Raise the top shelf and the 2nd lazy susan to the desired position.

I don't have either, so I'm not adding any experience but I personally love the Lemans type pullouts over the halfmoon ones. There seems to be less wasted space. Did you know Ikea now sells a Lemans type pull out? I saw one at their store this weekend, and it was very nice. I wonder though if it is rated for less weight than the original Hafele one. I couldn't find it on their website, but I see it here in their "Storage Solutions for Your Kitchen" mini-catalogue and the price is $169 Canadian.

single trays lay flat on shelves allowing you to keep the whole volume of the inside of the cabinet instead of shrinking the inside walls to fit around the lazy susan. So the sides and corners can store more packages etc. stack cans,,,bottle water etc in those spaces..

"Do y'all think that a new one can be installed without removing the counter top? " For at least some of the units available, yes. You may need to be able to cut the post to length though (typically using a tubing cutter).