Updated stats in bold from OP:
Matt Cassel is 19-29 in his 48 career games with the Chiefs.
He is 15-9 in games where we ran the ball more than we threw it.
A short list of quarterbacks Gus Cassel has faced throughout his career that might be considered "elite," or "definitely not Cassel in any way":
Rivers, P. Manning, Roethlisberger, E. Manning, Romo, Schaub, Flacco, Stafford, Ryan, Brees
Cassel's record against this group: 4-17 (.190).
Gus Cassel's Record Against Elite Quarterbacks, By Year:
In a week or two I will be able to update stats against winning teams and playoff teams as that stuff gets sorted out.