Toyota Tacomas are great trucks, so congrats on your new ride! Also, congrats on the chance to educate your dad on a little something called the Magnuson-Moss Warranty Act—it ensures that vehicle owners can modify their rides without automatically voiding their warranties. That said, it will likely void parts of your Tacoma warranty, as a lift kit, even when properly installed, will place added strain on parts of the suspension and drivetrain that could cause them to fail more quickly than they might under normal wear and tear.