Here is a video comparing the difference some 4mm roofing tar based material i stuck to the inside of the doors and roof and all over the inside of the mirage
The car drives and feels and sounds more queiet and feels more solid. Especially when you close the doors. It sounds less tin-ny. The product is just a huge roll i bought off ebay and i put 2 layers on parts that were very flimsy and hollow sounding but its pretty similar to the peel and seal stuff you can find at home depot or lowes. And of course you can use something more premium like dynamat or secondskin. Just that i feel that will be overkill as the loudest thing i hear now is wind noise which is still pretty loud because the glass in our mirage is so thin.
The interior comes out easy and so does the carpet and headliner. Should take about an hour to remove the entire interior.