Well I'm almost through with replacing mine and, although I think it was mostly a success, I do think that I spent too much on the headliner (HL) itself from the dealer. (Though I did trade the $$ for a bit of expediancy.)
The lowest I've seen for a complete HL has been like $250 + tax, S&H online. For me, (not wanting to wait for delivery) getting the HL complete meant that once I had it in hand, I was ready to start the replacement. (And hopefully the quality of the work is not in question. As opposed to me trying to do everything, rushing it and maybe create wrinkles or other problems.)
The main concern I had while doing mine was the swapping over of the foam pads/blocks on the top side edges of the HL shell. (I think these are in part to act as support/bump guards when people hold onto or hit their heads on the top of the door opening.) These pads were tougher to get off than I had expected, though perhaps I was trying to be too gentle. (I just slowly worked a thin putty knife under the edge and pried gently.) Also, and this would be the one good reason to recover the exisitng HL, getting the pads lined up on the new headliner (by hand, eye, and tape measure) is not a slam dunk.
(One side went well for me, the other is about 1/4" off at the front corner. The pads droop and stretch a bit as you handle them, and once they stick to the tape, they want to stay stuck! (I also used some spray adhesive since the tape seems a little out of place in spots.) I hope it's close enough. There is no built in way to locate these pads!!
There was a question as to the number of screws that had to be removed to get the HL out. I removed the 3 across the front and the 3 along each side, 9 total. (The rear most side screws are almost under some of the hinging mechanism. Becareful not to drop them!!) At that point the molding sagged enough to allow the HL to be pulled out. (With some attention needed in disengaging the contours of the foam pads from the side molding.)
I haven't put my headliner back in yet since I noticed a drop of oil coming out of the locking cylinder. Even though I saw no other sign of any leakage, I've decided to do the O-ring fix on that actuator. (Another $18 for the full kit off eBay.)
I'll make another post when I'm through, but the biggest thing on the cost of the headliner is from whom do you buy it, and/or how long or much work are you prepared to put into refurbishing the existing HL. (One can drive the car without the headliner though, so it's not like it has to be done all at one time.)
Hope that someone will find this information helpful . . .
(Thanks livefreeordie for the help!)