If you cap all of that off you are essentially stealing the compressed air that would be used for more instantaneous power by the factory recirculating system. Will a dyno or pass time show the difference, not likely. However, where you will notice the difference is when you are passing more than a single car or doubling an acceleration request. So to put this in English, you are on the road you stab the gas to pass, but then you want to accelerate again the VTA car might hesitate more than a factory BOV car. This is because the additional unused air that would typically be sent back to the intake flap is VTA.
If you "should" or "shouldn't" is subjective. I have driven both, and some kits are worse than others VS stock. If you are searching for a concrete answer yes or no, I would not VTA my car. Not for a single reason, but more of a mixture of the noise plus the reasoning above. Like I said, subjective question...so you will receive subjective answers.
