Just for fun I decided to calculate the density of the tallest block. Now this figure for the density is based only on the rentable/livable space and anything such as parking podiums, mechanical floors, elevator shafts, etc weren't taken into account. The final figure for the density is the ratio of useable space to total land area used (including roads).
Now I didn't check every single tower exactly since elite residence and marina 101 for example are pretty much the same as princess tower (area for each floor). What I did was find the area of all the apartments on a floor and multiply by the total floor count - 8 to 10 (this was to take away the podium and mechanical floors).
After doing this I came up with about 16.5 million square feet for the whole tallest block (this doesn't include parking podiums, mechanical floors, or cores. This is just the apartments). Now this is rough but I recon absolute minimum is 15m and absolute max is 18m square feet.
For the area of the whole place I didn't know exactly what to do but I counted half the roads around since they're used by the whole marina as well. Anyway, this is the area I took, I got 2.2m square feet. There's that little curvy edge at the bottom. I tried to make it up by taking in some water.
So you get a floor area ratio of 7.5 (isn't that very high? I can imagine that would be a Paris-like density of buildings but instead of them all 7 stories they'd all be 12 or 13 stories average)
Now this doesn't include:
1 G+unlimited undeveloped plot between marina 106 and pentominium
1 G+unlimited undeveloped plot between the torch and marina heights
The massive plot in front of the torch and marina heights.
Just for fun what would the density of the tallest block be had the marina sky towers been built along with two other 100-storey towers.
Marina sky towers - 5.8m square feet (I calculated this)
2 other towers - 2m square feet for the two
Total useable/rentable area: 24.3 million square feet.
Land to Floorspace ratio: 11
To imagine land to floorspace ratio of 11 I think if you think of Paris but make the average building 20 storeys instead of 7.