Jeb Bush and brother Dubya are biggest losers, Cruz biggest winner in South Carolina primary

Sources:

CNN for 2/20 results

Real Clear Politics for poll averages

Percentage-point difference between average and results, loser to winner:

•  -2.9% | Jeb Bush
•  -1.4% | John Kasich
• +0.4% | Ben Carson
• +0.7% | Donald Trump
• +3.7% | Marco Rubio
• +3.8% | Ted Cruz

And why add George W. Bush to the mix?

The Atlantic, 2/16/2016

(highlight added) 

If anything, Dubya provided the kiss of death.

Los Angeles Times, 2/20/2016