Hey I'm just a simple guy, I must have missed the clue that you where asking about its application on your Volvo on here on this Mercedes forum! But if it works for you it should make you happy I suppose. Having worked around engines of various sorts for the last 30 years I'm still a bit perplexed as to why or how it would be "good" to clamp a vacuum line because the engine is under high boost from a turbocharger. Generally speaking the more power generated by an engine will result in more vacuum being generated, and more vacuum being generated generally results in a pressure differential that causes the vacuum system to tighten up so to speak and therefore have less of a chance of a hose coming loose somehow. But maybe things work different out there on the left coast.

As far as holding under boost I suspect that it would depend predominately on the strength of the wire used but it's obvious that judging the amount of tension imparted on to the wire by that tool is pretty subjective and probably pretty difficult to do with any degree of consistency. But if form is more important than function it may be just what you want.

Maybe it might be worth considering why those stupid engineers at Volvo couldn't see the beauty of this method of clamping?