That's an amazing amount of hp to gain from just adding the inlet cam, from that I'm guessing you have a bt build.That's bad luck breaking the tensioner, as you say I would have thought the plastic tensioner would break first. I fitted an APG inlet cam to mine a few weeks ago and it's definitely perked up the top end above 6500 rpm it pulls stronger. I have been using virtual dyno to tweak the mapping and straight away there was a 30-40 bhp increase on the top end over anything I ran before the cam. So a very worthwhile mod on my car.
I'm only running a k04 hybrid so I wont see anywhere near that kind of gain but I'm interested to see how it performs.