Has anyone tried to replace the rear speakers with a sub and/or larger speakers?
 

If so, how did you go about it and how did it turn out? I'm thinking of trying out some 6.5 or 8 inch subs in their place.

I don't think it's ever been done. In fact, I doubt it's even possible. JK. Try looking in this sub forum first.

http://www.ft86club.com/forums/forumdisplay.php?f=27

I popped in 6.5, but did it badly and it sounded like it, went back to 3.5 infinity. If I was to try 6.5 again I think that I would cut the stick rear panel, and mount to it in some way, perhaps with a ring fused to the rear of the panel, and grills on top of the cutout.

I also went with 6.5's in the rear, using the 3D printed brackets

They are somewhat underwhelming with my current set up. Some sound dampening and a decent amp should help.

https://scontent.frir1-1.fna.fbcdn.n...62&oe=5AFC3F62

This is what I fab'd up for my rear speakers. I have another set up front too. They are almost like little subs, I am powering them with a huge 4 channel hifonics amp.
https://i.pinimg.com/originals/b9/d2...d5fabd7f63.jpg
https://japanwebshop.com/script/prim...1HN1L1W-10.jpg

I have this setup and it sounds amazing.

http://intl.jlaudio.com/car-audio-stealthbox-scion-fr-s

Didn't bother with the rear speakers, Focal's up front and the 10' JL Stealth Box in the trunk.. Sounds great




Oh, and sound dampening, lots of sound dampening

just cause im curious, what amp did you two use with your stealthbox?
I have a alpine mrv-m500

Kenwood Excelon Black 5 Channel Amplifier - XR900-5, but half that power is going to the Focal Components for the Front Stage. But because the car is so small, your only like a foot from the Sub anyway so why bother with rear speakers at all

That alpine will run the speaker fine. It does not need a lot of power to run it. As far as the suggestion of sound dampening it is a must. Lots of things rattle. Watch out for the rear view mirror. Have to glue it.