I know what he ment mate He just didnt know the answer to your question!!
I had the same with my 5zigen, with the blue tips, which I think are the same as the Invidia (it was an invidia wasnt it!!?!? King of Zorsts, True Dual ...) so not sure they are titanium, just Ti look. I think that they do it by adding a coating and then burning off so it may not be all the way through the pipe just on the outside.. If they are true Ti tips then I would have thought that it would have gone all the way through due to the density of the metal... But am not a metalurgist, and I bet your not prepared to keep rubbing to find out! And am not going to chop into the amuse to find out either!!