Hi I just bought an xlwb boxer I want to spray.foam. I bought some cans of no nonsense spray cans £2 each bargain I know! . Tested a can and cut back the foam only to find its lik we a sponge!! Are the 2 part foam.kits that sell for £250 or so the same on the inside. As if I cut it back to fit panels ot will be like a sponge!