Headers are simple in theory but time consuming. If you do not have a lift, you need to at least get the car up high enough for the angles you need to maneuver the new headers in.
Fitment can be an issue on cheaper headers and may turn into head ache. If you have a second car, then that would help in case it takes you a couple of days to get it all right.
Where are you from? A lot of the sponsors with shops have decent rates.
SOLD - 06 GT 371WHP/332WTQ
Sold - 1998 Camaro SS
Sold - 2001 Audi S4