How can you tell if the Subaru’s mileage is not correct?

[texaninla]

I just purchased a Subaru 2002 from a reputable dealership. The car had 23k miles on it, the tires were not the original..they are Cooper tires ...this threw up a flag but...any way to tell if the mileage has been tampered with? I know the odometer could be correct by a tool called http://www.xcardiag.com/wholesale/digipro3-odometer-correction-tool-mileage-tool.html.Any other tools？