I've tried searching for a detailed thread, but haven't found one on how to remove the carpet so that I can put down some soundproofing material. Does anyone have a good link or a good write-up? Thanks.

 

You have to remove the seats, the center console, bottom door trim moldings, and lower b-pillar mouldings. Adding anything under the carper is not worth it, marginal improvement if it's even audible. For sound proofing/deadening, only thing worth doing is inside the doors, at least it will improve the bass from your speakers and give the doors a more solid thud when you close it.

 

Up under the top Headliner also helps. Can switch out to the dual pane Acoustic window glass also.

 

Yeah maybe if you want to quiet the sound of rain hitting the roof, not much area to cover with the sunroof .

 

In the later years GS Lexus actually added more sound insulation deadening up there to make the interior quieter.

 

Would be interesting to see pics, someone drop their headliner

 

This is a bad idea bro. All that work and I guarantee it won’t go back together again right and it won’t decrease cabin db in the least unless you’re gonna somehow lay down ccf and mlv (decoupled of course). There’s just no room for that kind of job. Simply adding noice tar is pointless because it doesn’t decrease db at all - it simply quiets resonance from rattling metal. No road noise is decreased. Further, there are no resonances coming from the floor board - even with serious subwoofer upgrades thanks to the carpet.

You can ccf and mlv the doors and tire wells and trunk (not the headliner). And if you’re really serious, you’d see improvement from upgrading the windshield and windows. The car already has triple sealing, not much else you can do,

That said, before you do anything, find a location that you drive a lot and record the decibels with any phone app so that you can compare it to all the work you’ve done. In noisy cars, sound treatments can lower road and engine db’s by 10 or more. In a quiet car like the gs, you’ll be lucky to get a barely noticeable drop of 3db.