The University of Kentucky has hired Mark Stoops as their new head football coach. Stoops' was the defensive coordinator at Florida State University since 2010. So let's just take a look at Florida State's defense under Mark Stoops.
2010: Florida State's defense was ranked #24 in the nation, versus Kentucky's #78 ranked defense.
2011: Florida State's defense was ranked #41 in the nation, versus Kentucky's #95 ranked defense.
In 2012 (at the time of Stoop's hiring) Florida State was the #13 ranked defense in the nation versus Kentucky's #79 ranked defense.
All three seasons at FSU the defense was above average and this season is in the top 20. (Recall that FSU has played two non-FBS schools in 2012 - so who know if that matters that much.) On the other hand, FSU had the #105 ranked defense before Stoops arrived, so the dramatic turnaround and consistently above average performance seems to indicate that Stoops has a good defensive system that will benefit Kentucky's football program.