Holy crap only 20 bucks?? That is pretty awesome! The pistol also looks like it will actually work unlike the longshot pistol to!! This could possible be better than when they came out with the longshot or the titan even!
The spring has absoulutly nothing to do with the firing basically it is pushed forward then pulled back. When it is pulled back the air pressure increases and it comes to a point that the ball shoots out. I've only thought of 2 ways to mod it. coverup some of the air holes on the part that pushs the air out, that might focus the blast and get more power out of it. the other way was to add more resistance like electrical tape onto the end.