If you tape some plastic down over the carpets BEFORE removing the tunnel, you eliminate the "goop" on the carpet issue. There is also a tool for windshield removal that is like a screwdriver handle with an "L" shaped blade that works well to cut the sealer on the tunnel. Just work it along the seam and you can cut through most of the nasty stuff.
About the only substance I have ever seen that was nastier than the tunnel sealant was the stuff AC Cars put on the 289 leaf springs. They were wrapped in canvas soaked with the messiest stuff known to mankind. Even sealed in plastic for shipping this stuff would get all over!
