I've currently finished 50sq ft.
I have another 50sq ft with which i will finish the floor, the doors, the rear shelf (double sided) the boot lid and perhaps double up on the roof with a few more sheets. I still have a few bits (about 5sq ft) to do in the boot, but then the rest will be used to double up on essential bits. I'm not saying that i've got enough to finish the job, but i'll just have to buy some more if it is the case. :)
If anyone is interested in how much of an improvement this has made... my opinion is that it has already made a drastic improvement... and that's without any audio equipment... road noise is down to a very low hummmmm...... :D
Another quick question: What size rolls did you buy and how much are they each? i plan on doing the boot, rear shelf and doors, dont think i'd have the patience to do anymore!