Originally Posted by 04scoobywrxwagon
I heard its "better" to wrap it from bottom up, to have a "shingle" effect if water gets down in that area, so the water just runs down and off instead of in between the wrap..
It is. It also makes the wrapping process more difficult. Harder to estimate your length required but still very doable. The difference is probably small in the big picture. Most of the people wrapping DPs go the turbine to cat-back direction and never think about this.
The best thing you can do is use the LR type wrap (i.e. DEI Ti wrap) and forget that old crap header wrap.
Yes on the new O2 sensor. Yes on the anti-seize on the threads. Just do not get anti-seize near the sensor's business end, it will affect it's accuracy and lifespan. Also notch the RHS manifold heat shield while you're in there, only takes quick snips or grind. Helps if you ever have to remove them again, no need to remove the O2 sensor first. I usually copper spray the turbine gasket for safe measure but it is not required. You could also modify your OEM DP heat shield and reattach it over your Invidia...more heat control and some elusiveness.
Good luck, tune the ECM for the DP, and enjoy