[otrs] More search attributes in the 'Link ticket' search window

Guys, I would like to add more search attributes to the 'Link ticket' search window. By default it only contains ConfigItem# and Name. For us, the critical one would be Serial Number which is a custom field. I can see there is an extension that apparently can do that: KIX4OTRS My questions: 1) Does anybody know how to add those fields in native OTRS? 2) Do you use KIX4OTRS and if so, how reliable it is and what kind of issues can you expect during upgrades. Thanks a lot -- Robert