Foam shit in sills

[Dogs Danglies]

I've heard alot recently about that expanding foam 'shit' that is pumped into the sills/chassis and supposidly is 'better' than a roll cage. Personally I cant see it being better than a roll cage? I first heard about his a few years ago when I was into VWs and I was told that it works, but not for very long when the foam starts breaking up/losing strength, then its basically just useless extra weight as you cant get it out again, and is also a nice water trap to rust your car from inside out.

What are al your views on this stuff, if you reckon its the bollocks I might give it ago. If not I'll just put a cage in anyway, and take it from there.

Cheers.