Hi,
Well I don't own an 05 but I do work in the Automotive field. The cover is mainly there as dress up for the consumers who rarely look under the hood. It also tends to keep the more timid "garage techs" out of messing with the engine.
How ever I did get to test drive an 05 GT limited and found it to be much more than I expected. Fit, finish, power, and "MSRP" price.