Frekey,
You'd only be talking about a difference of a few thou of an inch which would make negligeable compression increases. You would get a bigger increase in compression just from carbon deposits in the compression chamber.
Besides, thinner head gaskets provide much less sealing capability.
Now, if you had an old small block V-8 you could machine the heads and then deck the block a few thou to increase compression a point or two.
You'd then probably need a new cam to maximize the new potential and you'd probably have to run 94 octane or higher.
All-in-all, it's probably not worth all the work and expense.
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2006 Grand Prix GXP, Black Cherry