@TBbadmofo: MKS is used to increase the precision of the engine. The engine uses the type
float and that type only has 32 bits of precision. By keeping items around 0.1 to 10 units (meters in Farseer 3.x) we allow the engine to use more bits for precision.
To allow Farseer 3.x to use pixels as units (highly unadvised) change Settings.MaxTranslation to something like 200+ and it should allow bodies to move in a normal manner. (untested)
A much better solution is to simply add a scaling constant, say 100 pixels per meter, and scale everything you draws position by this. Simple and easy and you get to keep the precision.
Some people don't like doing this because it can be hard to align the debug view with your shapes or vice-versa. The solution to this has been provided in other threads. (You search for them... I'm busy playing Terraria)
Also some people can't find the perfect meter size to represent their shape . The solution is to measure your shapes pixels, say a 100 pixel wide circle, and then divide by the pixels to meter constant. You will then have the perfect meter size of your shape.
I hope this helps you.
@nkast: I've never heard of MGS. Could you elaborate?