In my experience, replacing a hard-wired power cord isn't difficult as much as it is messy. If the replacement cord is thicker than the stock cord, you might have to drill a bigger hole into the chassis and then get a larger grommet. Another option is to remove the old grommet and not replace it, thus allowing sufficient clearance for the new cord without drilling a bigger hole. Of course, using the latter approach, the power cord won't be well secured so you'll probably want to do something to insure that the cord stays in place and is protected from the metal edge of the chassis. A simpler possible option is to enlarge the inside of the grommet by filing down some of the interior of it, and then using it with the larger cord.
