I used a circular cutout in a brace to hold a port a couple subs back. The tube was was a fairly tight fit in the brace but despite that when I cranked up the sub it still vibrated and the port tube just made it all that much louder. Not to mention, it was a PITA to get the port tube to line up exactly with the hole in the brace as the outside flare was flush mounted and I didn't have any wiggle room on that end either.
So the next time I decided to try something different and went with the foam. I didn't actually use the pipe wrap but had suggested that as it is easy to find, I had some of the thicker 1/8-1/4" foam sheets that comes as packing material and I just wrapped it wound the port tube enough to make a snug fit in the brace, put a couple zip ties on to hold it and shoved it through the hole in the brace. The foam was just enough to hold it in place and most importantly, eliminate any vibration of the port against the brace.