It may be small potatoes in the long run, but Astros pitchers allowed the fewest runs per nine innings during "transition" innings than any team in the NL. "Transition" innings are those innings where a manager sends his starter out there, pulls him, and then goes to bullpen before the inning is over. In 64 such innings, the Astros allowed 95 runs. Expressed in terms of RA/9, it's 13.4. Here's the NL chart from Baseball Prospectus 2009:
What we can also see, is that Cecil Cooper was more willing than most to give his starter the hook in the middle of an inning. Our bullpen was highly effective in 2008, as the low number of leads surrenders begins to indicate, but it was also overused. With two aging set up men, and a long reliever coming off elbow surgery, it will be important for Cooper to judiciously use his bullpen arms.