I did not want to buy spacers or make my own. Using the stock ones worked out but you do have to understand that you will be destroying your old speakers.
After taking off your door panel, take a razor blade and cut around the speaker circumference.

Lift up the speaker cone to reveal a plastic framework holding the speaker in. Take a pliers and just break them off. It is not that hard. Don't forget to cut the wires to the terminal.

Next solder 1 foot of speaker wire to the terminals in the enclosure and then to your speaker. Don't forget positive and negative. The larger terminal is the positive one.

When you put the speaker in the surround, make sure that the speaker terminals are 180 degrees away from the surround terminals.

Drill your holes and then mount the screws.

When you are done you should have a tight fitting speaker. You were just going to throw out your old speakers anyways.

 

Or you couldve just bought Alpines, they come with mounts.. A lot less work and amazing sound. And then you couldve sold your stock speakers...

 

An interesting solution to your problem. Never would have thought of that. In my own Box, I made a set of mounts from 1/2" Baltic Birch plywood I had on the bench. 30 minutes work and done. In deference to Dark Gecko, the only buyers for stock speakers would be people who are selling their Box and have taken out their aftermarket system. But then comes the challenge of remounting them with the factory rivets removed!

 

What I said is what I did.. Someone bought mine.. People sellin thier B wouldnt be the only reason to buy stock speakers, couldve blown one, whatever the reason youd be surprised what people will buy, theres always someone..