The flex is there so when the headers and crossover heat up. The expansion, especially in the crossover expands outward and tries to push the headers outward. Causing crack in the underside of the header tubes going into flange, or at the collector. The wieght is not that big of a deal with this size turbo, and 16 guage header tubing helps. the flex also helps me as the builder. It gives me a little room for error. Not really in my fitting. But ever time you weld a joint, it expands and contracts and throws it all off a little. Then after I finish the headers, I have to mill them get the flanges straight again, which throws things off a little some more. Everything gets test fit before it goes out to make sure. But it helps.
Glad to see you back 411, thought you where outta her...