So I would like to contribute. I know Ron was against telling the sizes but I would like to give sizes to show a reasonable size for the turbo wrap material used. Or was that for his header wrap how to?
I bought the wrap and realized I had enough for two wraps my 02 wrx and my friends 09 sti
I slightly tapered the under wrap about 1/4"~1/8" but for the most part it was a square cut.
I cut the under wrap directly down the middle but to one side of my mark. This left me with the two over laps with the 1/8" smaller one on the bottom.