Since nobody has yet to respond, here's some info from a relatively new flashaholic.
The XPR112 is the Xenon version of the PR112, KPR112 is the Krypton version. Xenon is brighter than Krytpon. So all things being equal the XPR113 should be brighter.
If you want it brighter and whiter you can use a KPR113 which is 4.8V. This will be an overdrive and those usually produce whiter, brighter light. Don't try to overdrive a Xenon bulb though.
Maybe someone with more knowledge will chime in.