I am starting to think that the variance on your particular header was larger than the 1/2" farther than the cast iron header that has been stated in the thread.
Lets get some real measurements that can be compared:
On the car:
How far it is from the two driver side turbo flange bolt holes to the brake booster? Those should be fairly reliable measurements.
On the head/header:
How far is it from the edge of the head to the same turbo flange holes?
How far is it from the back side of the head to the same turbo flange holes (backwards toward the firewall)
That way we actually have real information about the placement of your turbo. It might be that it is both farther to the driver side and farther back than we think making the fitment a real issue.
The engineer in me says that we need to get some real reliable measurements that we can compare and only then can we tell what is going on.
Then basically if it won't work due to those measurements Chris should say that you are right and it won't fit.
The options then suck a bit for you but it seems that they are probably:
1) Sell the damn thing to someone that doesn't have a shadow.
2) Change the brake booster to the thin one (not sure if you would want to)
I think when it comes down to it if it doesn't fit the most you can really expect considering that it was used on your other car for quite some time is for Chris to say:
"Sh!t well I guess that particular header won't fit the Shadow with the big brake booster."
Getting a solution to make your header work is the first important thing if it is at all possible. But if not I think it just sucks and there isn't much anyone can do to fix it.
-Rich