someone here did fit one to his xtz after having had the kev mods (both) and found the boosterplug even a tad bit better.
anyhow you will need an O2 optimiser, either kev's or the one supplied with a power commander.
i did have an O2 eliminator (cheap sollution) and didn't really have any drawbacks. i did put kev's O2 optimiser on now.(slight improvement over the O2 eliminator ,imo...)