its not cheap..... its not removable (i can attest to this)
as far as legality goes im not certain (mine has been filled by the previous owner)
be warned,
1)again depending on the design of the car, some wiring might get 'buried' in the foam.... and its a horrible job is the wire putus in there....
- now this i had to do, one of the door switches was not working when i got the car, and i thought, yeah a simple job wonder why the previous owner never got around to doing it..... its cause the damned wire snapped in the middle.... had to keep trying over and over to get the wire through the foam, managed in the end but wow was not fun
2)it can takung air (depending on the design of the car), some of the drainage pipes might get blocked and its no fun drying it all out and dealing with it. I'm not sure if it actually soaks water? but i really hope not...
-i have heard of one guy who did this on a prelude with a sunroof, he had one issue... the drainage pipe for the sunroof goes down the pillar and out at the bottom somewhere.... yeah his got blocked somewhere and the car started leaking.... on the roof and then later by the passenger's feet, i remember him troubleshooting for months looking for a leak, until he found that basically the sunroof drainage had been blocked... dont know if he actually solved it....
-maybe i should manually plug all the lobangs and pour oil into the sills... (should work i guess since ppl have been doing this to deal with rust just in case mine masuk air, mine had lots of 'ruang' in it near the top)
vr2 you know the boss?? haha maybe mine was done by him