I actually think that hiding it is a good policy
Why on earth do you think that! 
That statement must be THE most stupidest thing ever posted on GolfGTIforum !!! 
Not very good with the English language then mate?
English language may not my strongest attribute, but I don't think I'm too bad. It does, however, show you have to stoop so low to the gutter, in trying to exert your indefensable comments.
However, I am a very highly qualified Motor Vehicle Technician, and a very experienced "spanner monkey" too. So I think I'm just slightly better positioned to voice my opinion, compared to you.

I am also lead to believe other regular members of this, and other fourms, appreciate that my posts are based on valuble experience and knowledge, and that I am generally trustworthy, and don't post bollox. Or maybe my specticles are the wrong shade?
Oh, and I don't know where you got the idea from that I was your "mate"!
Well opinions are like assholes and some stink,
You should know, because it appears you like burying your head up your own ar$ehole, when you don't want to listen or accept what others have to say!

but my point was that if you don't go blowing or showing, at the very least the Stealer is not going to get a whiff of the fact the car has been played or tinkered with.
WRONG - the stealer WILL know the car has been "tampered" with. Just like the stealer will be able to detect if non-VW approved engine oil is used.
Can I suggest you remove those very restrictive blinkers you appear to be wearing. They really are only meant for creatures which have an extremely limited intelligence, such as horses.
That is worth something to a lot more than just me.
Explain.
I am going to be doing some research in to this when time allows as I am keen to map my car, but rather than deal with heresay from someone off a car forum, I would prefer to deal with fact.
So, where to you propose to get your "facts" from, then?

I also plan to see what GIAC have to see about some of your comments to see if there is any truth in them.
And . . . we all await with baited breath.