1) It definitely helps if you have someone helping you.
2) Get the car up on jackstands so you've got plenty of wiggle room under there.
3) Someone should feed the headers up from the bottom. You'll probably have to rock/rotate them in on the drivers side I think. Passenger side is pretty clean on my car. But I don't have AC, so I don't know if that will pose a problem
4) The person on the bottom feeds 'em up. The person up top grabs a hold of 'em and inserts a header bolt on each end. Then that person slips the gasket on, then starts the bolts into the head just enough to get it to hang on it's own.
I know that a couple of the bolts are really nasty as far as getting a wrench in there, as the bolt head pretty much touches the header tube until it's threaded entirely into the head. I believe on the headers you have you'll find that those trouble spots are already nicked a little bit to make it easier. I believe those pesky bolts are on the driver side, but there might be one on the passenger side as well.
When getting 'em all started, it helps to have that person underneath the car holding it place and occasionally giving it a wiggle so you can get the bolts started.
Overall, it's not a bad nor hard job. Besides the pesky bolts mentioned above, the other potentially tricky part is getting the existing exhaust to mate up nicely with the collector. That can take a fair amount of finagling as well.
For fun, once you have them mounted, you can always fire the car up just to hear what it sounds like with "open headers". heheheh...The neighbors love that!! :L But don't do that for too long as you don't want to melt your underside!
(Oh yeah, two last comments... 1) Make sure you are exempt from any emissions testing! 2) Do a good job on cleaning the mating surface on the heads (and headers to while yer at it) to ensure you get a good seal between the heads and the gasket.)
