Performance benefit using StringBuilder instead of StringBuffer in org.drools.util.StringUtils

Any chance we can get some performance improvement by replacing all uses of StringBuffer in org.drools.util.StringUtils with StringBuilder?
If the minimum JVM version for drools is 1.5 StringBuilder is more efficient than StringBuffer for all the current uses in this code.

From the javadocs:
'This class is designed for use as a drop-in replacement for StringBuffer in places where the string buffer was being used by a single thread (as is generally the case)'