Mmmmm, be carefull as it CAN bring on a lack of power at certain parts of the rev range - mainly top end. Its due to the lack of back-pressure that taking out the middle box brings.
I de-catted mine recently and noticed a slight improvement low down but it does seem a bit flater than it was high up the revs, taking out the center box may well just make things worse, well on mine anyway, and I've heard on other forums that it definately can.............