PCIII- how many extra HP

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G'day all. Quick question for those in the know please, how many extra rear wheel HP would you expect to get from a PCIII ? I've got a K&N Filter, R55 full yoshi system on the K8, and yesterday had a PCIII installed and custom tuned. He said before the tune I had 165 rear wheel HP, and after 171.4. Does this sound about right? I was hoping (praying) for more? Any help in answering greatly appreciated. Cheers.