Another point that has been overlooked (although it was mentioned a few pages back) - even if 40% of young</> Musims support Sharia law, you can be almost certain that number will fall as they grow older.
The figures from that same survey point up this fact - as people get older, they get progressively less radical.
I myself used to be a fire-breathing socialist, and now I'm much more 'centre-left'.
You get older, you buy stuff, you mellow out.
To summarise, you go from listening to Iron Maiden...to listening to Katie Melua and you won't even notice it happening.