Using the PShape.setX() methods and PShape.disableStyle() are two alternative ways of changing the properties of your shape. With the first, you just set the values you want to use for your shape (but note that setFill() needs a color argument, don't pass individual rgb components to it, see the example below), while with the second, the shape will be drawn using wherever parameters have been set with fill(), stroke(), etc. So the output of the following two sketches should be the same:

1. // Using disableStyle()
2. PShape test;
3.     
4. void setup() {
5.   size(1000, 700, P2D);
6.   test = loadShape("Guy_20130912.svg");
7. }
8. 
   
9. void draw() {
10.   background(70, 20,10);
11.   
12.   test.disableStyle();
13.   fill(200, 200, 0, map(mouseX, 0, width, 0, 255));
14.   stroke(255);
15.   
16.   shape(test, 50, 50);  
17. }

and

1. // Using setFill(), setStroke()
2. PShape test;
3.     
4. void setup() {
5.   size(1000, 700, P2D);
6.   test = loadShape("Guy_20130912.svg");
7. }
8. 
   
9. void draw() {
10.   background(70, 20,10);
11. 
    
12.   test.setFill(color(200, 200, 0, map(mouseX, 0, width, 0, 255)));
13.   test.setStroke(true);
14.   test.setStroke(color(255));
15.         
16.   shape(test, 50, 50);  
17. }

I hope this clarifies the issue.