should be 6.5" in the front.. you can get the SAPs from crutchfield.com, my friend needed em for his Polk/MOMOs... they make be called GM SAPs, can't quite remember.
Oops, actually they are 6.5", the right size for the camry. I just pulled out the manual for it. In the back there is a "cut-out template" with what looks like a SAP design..
I took a small piece of metal (specifically an unused PCI slot bracket from the back of my computer), drilled two holes in it as a "bridge" of sorts to line up the screwholes to make the speaker fit in the hole. It's not exact, but the fit is tight and it's a really easy way to do it. Cheap too.
Edit: Of course I sawed off the remaining unnecessary metal so that it wouldn't get in the way.