Actually I haven't heard much of the gasket itself failing. The UIM itself can fail though. In the EGR bore it will get hot and through the expansion and contraction cycles it can crack or rupture. The cooling passages to supply the TB are directly next to the EGR bore and will fill the LIM with coolant and possibly cause a hydrolock. The other thing to keep in mind is that the LIM gaskets also have a high rate of failure and should be replaced with the best available. Currently the best replacement for the LIM gaskets is the GM aluminum gaskets.
00 Regal GS: All kinds of cool stuff.