Bondmanp -
If you dynamat and want to do it it correctly, you dynamat everything. From door panels to trunk floor and lid, to roof and floor to wheel wells and firewall. Any panel inside the cabin and trunk that could be removed that has some room under it to place dynamat should be covered. That of course is for best results. And considering your vehicle, you are looking at more than $400 in dynamat to do it right.
Now, instead of removing all the panels more than once you may want the rest of your audio gear you are going to install handy so you can install it at the same time.
Now you said you don't want to remove the HU. I understand completely. However, I have done a few installs where the HU wasn't changed but the speakers were upgraded. Sometimes it actually sounds worse. You could try the higher-end cable route and replace your speaker cables. But I've never done that myself so I can't comment on the improvements on a stock system.
One thing you could do on a stock system to at least get bass you can control is get a splice box that taps off your rear speakers wires and gives you an RCA line-output for an amplifier. Then just make sure you get an amp with a remote level control that you can place in your center console or mount on the dash. Put one nice 10" Alpine Type R or a JL W6 in a sealed box and viola! Bass that won't interfere with your music that you have control of. You may be able to use your subwoofer wires and just disconnect that thing entirely. Up to you.
Total cost of all this would be approximately $1,200 if you install it. But it would be very quiet and great controlled bass. You might not mind your stock stereo after all. I've done a few of these installs before as well and I only received compliments. If you need any other tips you can always send me a message and I'll help out any way I can. Good luck
If you dynamat and want to do it it correctly, you dynamat everything. From door panels to trunk floor and lid, to roof and floor to wheel wells and firewall. Any panel inside the cabin and trunk that could be removed that has some room under it to place dynamat should be covered. That of course is for best results. And considering your vehicle, you are looking at more than $400 in dynamat to do it right.
Now, instead of removing all the panels more than once you may want the rest of your audio gear you are going to install handy so you can install it at the same time.
Now you said you don't want to remove the HU. I understand completely. However, I have done a few installs where the HU wasn't changed but the speakers were upgraded. Sometimes it actually sounds worse. You could try the higher-end cable route and replace your speaker cables. But I've never done that myself so I can't comment on the improvements on a stock system.
One thing you could do on a stock system to at least get bass you can control is get a splice box that taps off your rear speakers wires and gives you an RCA line-output for an amplifier. Then just make sure you get an amp with a remote level control that you can place in your center console or mount on the dash. Put one nice 10" Alpine Type R or a JL W6 in a sealed box and viola! Bass that won't interfere with your music that you have control of. You may be able to use your subwoofer wires and just disconnect that thing entirely. Up to you.
Total cost of all this would be approximately $1,200 if you install it. But it would be very quiet and great controlled bass. You might not mind your stock stereo after all. I've done a few of these installs before as well and I only received compliments. If you need any other tips you can always send me a message and I'll help out any way I can. Good luck