You could try telling the State to repair the expansion joints in the roads so the car doesn't bounce so much.

In addition to the 4 firewall screws, there is a screw on each side of the lower dash that attaches it to the A pillar. If you want to try to tighten the 4 firewall screws, you need 2 people. Remove the wipers, remove the cowl below the windshield to expose the screws. Loosen the bolts by the A pillars. Have the other person shove the dash forward as far as possible, while you snug up the 4 firewall screws. Tighten the A pillar screws and put the cowl and wipers back on.

There are 'fixes' to tighten the firewall attachments, look around on Matthew's web site. They require the complete dash removal which gets a bit messy.

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Keeping it running is better than buying new