I know this subject has been beaten to death, but was curious about the fitment of the Polk 401's in the front and rear of a GL1500 SE. The rear speakers in particular have a very confined space (depth) to fit in. Has anyone installed these on a later model 1500SE without depth or mounting issues because of the larger magnets ? Have seen comments both ways. Most say they fit perfectly, but have seen comments about depth problems, as well. Also considering the 401's for the front, since it is technically the same speaker as the 501, with a smaller mounting frame. Is the larger 501 frame needed in the front to reach the mounting screws ? Any help would be appreciated.