Polk EX 2565 set mounting in an A3 GTI
Mounting of the Polk EX 2565 woofers is trivial. They fit in the factory locations and use the factory grilles with zero modification needed.
Incidentally, if you have a blank slot bracket from a PC, it is an excellent tool for popping the speaker grilles off. It is far less likely to cause damage than a screwdriver is.
I chose to mount the crossovers under the rear seats. I used the factory wiring between the front door speaker and the dash tweeters, because I didn't feel like taking apart that whole mess of stuff that goes through the door.
The Polk EX 2565 tweeters fit into the stock locations, here's how:
Front tweeters in dash:
I cut out the original speaker from the round mounting plate. I found a couple of old round telephone wall plate covers and painted them black. I enlarged the 1 inch hole in the plate to 1.5 inches, and expoxied it to the underside of the speaker mounting plate. Then, I epoxied the Polk mounting ring to the top of the telephone plate. Everything fits very nicely and is completely invisible once you put the cover back on.
Rear tweeters in door panels:
I ground out the glue that holds the tweeters into their holder with a dremel tool. Then, I ripped the tweeter out and pushed the grille out from the back side. If you remove the mounting ring from the tweeter, it will fit precisely into the hole left behind from the factor tweeter.
The result is nearly stock. If you take a little more care than I did when you glue it, you won't see the glue around the edges.