I just picked up some new speakers to replace my older ones. I was thinking of taking my 6 1/2" fronts and cutting new holes in the back doors for them. Has anyone tried this before?

 

My fronts are 5.25 but I cut them for 6.5, here's the issue though, not the size of the speaker but the depth...this is what is much more likely to cause an issue, make sure this is ok before going through with plans.