How hard would it be to fabricate a speaker mounting ring to use a set of 5.25" components in a coupe? Just make a template and cut out? How thick/thin would anyone suggest it to be?

Reason being...my buddy just removed his stereo system and is selling off his Focal Polykevlar components for cheap.

 

Not hard at all, granted you have some way (drill & jigsaw) to cut a piece of MDF with. Simply remove the OEM speaker and use its outline as a template. Now cut out the hole for the 5.25" speaker you want to put into (centered or offset, whichever works best for you), and you're done...

 

Could you not use a prefabricated template such as what Crutchfield offers (Something like below)?
http://www.crutchfield.com/S-SZMoOwE...g=103200&avf=Y

 

I think I might try to angle the speaker up towards my ears because right now the speakers face slightly away from passengers.

Anyone know how thick I can make the template? 1/4" ... 1/8" ??

 

1/2 to 3/4" is fine for a spacer. Or do 1/4" for the base template and make the actual ring out of 1/2" to make a total of 3/4" spacer. (use wood glue)