i won't take up for mark by any means, but the melting point of titanium has nothing to do with bluing.
air holes in the welds will cause it faster than anything, the thinner it is the faster it tints, running lean will do it and egt's of a bike of the track are astronomical. they can hit 1200f+ and stay there easily. most of the bluing happens where the flow is disrupted like in a reducer, in a bend or a connection where the airflow is not smooth.
as said, i won't knock on his products as everyone here already knows... but even a good quality piece will blue easily.
03 RC51 - 135whp via lots of stickers and a few parts. tuned by hord