True - catted DPs will work fine tuned or not, and will improve performance both ways, especially low end due to earlier turbo spooling. non-catted only cause a code from the last O2 sensor and nothing else.
True- I had my PPE catted DPs ceramic thermal coated.... dyno showed no difference in performance... I love the look, but it just doesn't work like what we used to do the headers on our old big block engines.
So... consider coating for aesthetics only.
IMHO blankets are unsightly and in out small crowded, sealed engine compartments I would worry about proper air circulation causing earlier heat soak and perhaps elevated underhood temps.