D3 map SVG performance

I've been struggling the past few days to optimize performance on a D3 map, especially on mobile. I am using SVG transforms for zooming and panning but made the following observation: the overkill comes from path strokes used to fake spacing between countries.

I have uploaded a pair of sample maps for comparison:

http://www.nicksotiriadis.gr/d3/d3-map-1.html

http://www.nicksotiriadis.gr/d3/d3-map-2.html

The only difference between the two maps is the stroke path along the country paths, and the difference in performance is even noticeable on desktop devices - but more obvious on mobile. Removing the path strokes makes mobile performance a breeze..

I tried all kinds of svg stroke shape-rendering options without significant results.

Now to the question. Is there any way to remove a thin border from each country to fake the spacing between countries instead of using a stroke?

If anyone else has a different suggestion I'd love to hear it!

Update: Attaching explanation photo.

What I have drawn is this. The red arrow points to the country joints. When adding a stroke in a color same as the background to the country paths (here depicted in dark grey color) it creates the sense that the countries are seprated - however this adds a serious performance hit on mobile devices. What I am looking for is somehow re-shape the countries paths so that their borderlines are where the blue arrow points, but without having a stroke.

Update 2: People seem not to be able to understand what I am looking for, so I am updating this in order to make the question even clearer.

Let's assume that the original countries paths are shown on the left of this image. What I am looking for is a way that I can somehow 'contract' the paths inwards so that the newly created paths shown in red, leave enough empty space between them that will 'emulate' a stroke between them.

Doing this, will leave no use to having an extra layer of strokes, thus gain performance from only using paths instead of paths+strokes.

Update 2: Hello again, I seem to have found a half-solution to my problem. I managed to extract the topojson to shapefile, edit the shapefile the way I want (used a program named OpenJump), but the conversion takes away all the topojson properties I need - id, country name, so I can't convert back to the original topojson.

Does anyone have any suggestions?