So i jus got my headers in and i'm looking to wrap them with 2" exhaust wrap. How much should in expect to use? I need to figure out if i need to get 25', 50', or 100'.

I would not recommend using the wrap on a street application, the best way to go is ceramic coating inside and out. The wrap has a tendency to cause the tubes to corrode faster than normal. The wrap traps moisture next to the steal tubes, some claim that painting the header first helps but I have yet to see a paint that holds up to the heat.

There is a slightly cheaper method besides ceramics, it was called "Flame Spraying" back in the day, basically molten aluminum sprayed on which gives a rough dull kind of finish. The aluminum is very soft and can be burnished to a satiny kind of sheen which looks better in my book.

Good luck.