Mine is one piece. I should have used dynamat or someother type of non jute padding as it's hard to get it wrinkle free w/o the jute separating.( glueing it down) Regular house padding would have been better for the tunnel. Fill in any ripples in the metal with padding and get it as smooth as you can. Cut a piece larger than you need, lay it on top and try to get an idea how it wants to lay, then start trimming. Might want to get the back of it hot in the sun so it will stretch better. Be careful what carpet you buy. Make sure it has a backing. The non backing "auto carpet" sold at Pepe boys and othe carpet stores doesn't have this backing and is crap. It's more of a felt and is used for speaker boxes. It lays down nice and easy, but doesn't hold up.
Take your time, it will take allot longer than you think, especially if you do it right.
I used 3M trim spray adhesive. Spray it down all over (the tunnel) and work it from the top of the tunnel to the bottom. Don't go front to back or vice versa.
Don't cut the shifter hole til the end. You might have to cut it a bit earlier to get some wrinkles out. Cut it smaller than you think you have to, then trim later if you have to. Mine is almost too big. You might have to work it backwards ( bottom to top) once you cut the hole to get some wrinkles out.
Pull down on it and stretch it while you stick it to the glue on the tunnel. You'll figure it out. I don't like the two piece look.
If you don't have a radio console it might be tough to get it right as I have a fold under mine ( that you can't see) that helped w/ the wrinkles. it doesn't go all the way forward there either.
If you can MS your car, you can do this.