Installed Blaupunkt 4x6 GTx-462 DE Speakers in the rear
 

The rear Polk 4 Inch DB401 Speakers didn't last long so I put in Blaupunkt 4x6 GTx-462 DE Speakers. I paid $42.99 plus shipping from Amazon. They're rated at 35 Watts RMS (160 Watts Peak) and have a better Frequency Response of 80 Hz to 22 kHz.

I decided to mount the speakers flat against the Grill. I cut the old mounts for the 4inch units and used them to secure the 4x6 units across the longest dimension of the rear opening. I then sealed the air gaps using cut pieces of Corrugated Plastic (old Garage Sale Sign) secured with Goop Adhesive. I suspect the Voice Coils may last longer due to the flat mounting versus the angled OEM mounts. The Blaupunkts sound better than the Polk Speakers probably due to the better frequency response and higher peak power handling capability.:biggrin:

Thanks for the write up this will be coming in handy within the next few months. My drivers side sounds like garbage now. Thank you.

I didn't see this write up before doing mine so my dyi is a bit different. I had some 4 inch speakers laying around from a different project, they were 2 way speakers, a woofer only 4 inch would have been preferable.\
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Of course you have to remove the carpet kit from the rear first, if you have the cd changer that needs to come out as well. On the right side there is the latch cable for the fuel fill door so you just need to move the carpet out of the way.\
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Remove the 4 screws that hold the speaker assembly.\
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Clip the wires off to the woofer or de solder, if you have the 10 speaker version like mine, it's likely your tweeters are fine\
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Now look at the picture in the first post. Instead of trying to pry apart the glue holding the speaker to the speaker tube, I cut off the radials of the speaker itself so that they are flush to the diameter of the speaker. Note: you will mount the new speaker directly to the outer ring remnants of the old speaker.\
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Now trim where you cut the radials so you have a smooth circle.\
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Mount the new speakers, if done properly it should snap in flush.\
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Bend the tabs for the screws upward so parallel with speaker tube, put some screws in and re solder the wires to new speakers.\
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This method has the advantage of still using the OEM speaker tube as intended.

I just used this thread to replace a speaker and thought I would update it with what I did.

1. After breaking the glue loose you can rotate the speaker with a little careful pressure from a long screwdriver. The you can carefully pry the speaker up.

2. Found some speakers that were as close to the right size as possible.

3. Used a dremel and exacto knife to cut slots out in speaker cone where the original slots were.

4. Insert speaker in slots and used some black silicone to secure it

I will let you know how it sounds, but it has to better than the blown speaker in there now.

I designed my own adapter to be 3d printed for putting 5.25" speakers in the back of my 318ti. Here's a link if you want to download it and print your own: https://www.thingiverse.com/thing:2844756

Wow, that's amazing!! Thanks for sharing your design. Too bad I just zip tied some 4 inch speakers in.

Thanks for sharing
 

This is great to know. If I get my Ti running I'm doing this!

Just finished repairing my rear speakers, you don't need to destroy the mounts or get aftermarket ones. A cheap foam repair kit (< $40) is all it takes, I made a quick video showing how:

https://www.youtube.com/watch?v=BEnLB7NbbX0