I have had the BPR CAI on my previous ute (BF XR6 N/A). I had it tuned using the xr8 snorkel then changed to the BRP unit and it did make a significant seat of pants difference. I did not get a dyno comparison becuase I lived a good 10hrs from the tuner, and using a different dyno wasn't going to be an accurate comparison. In my opinion I reckon they are a good bit of gear. I wouldn't be too worried about the tune if you are changing your exhaust, unlike the turbo engines, you won't be running any risks without retuning, you just won't be getting the most out of your enitre setup.