You have to take the spark plugs out too. I usually put the rear wheels on ramps and the front of the car up on jack stands. The car needs to be raised pretty high because the headers go in from the bottom on an angle.
you had to take the plugs right out? oh. i didnt have to take mine out, but hey if it gives more clearance than ya you may as well, since there isnt much clearance in there anyways