My new dash cost £90 ($135) from a breakers yard. You can then just unscrew the front panel with the rings on and swap it on your clocks. However, I think the black dials look strange with the rings as the sport dash has grey clocks.
The light or dot is not to show tampering and will not illuinate if the mileage differs between the clocks and the CPU. It illuminates to show the clocks are not PROGRAMMED to your vehicle (ie wheel size etc) . I had mine repragrammed by a 'mileage correction firm' who charged me £40 ($60).
If you cant be bothered with the reprogramming, simply find a crashed 330 (coupe or saloon), take the face off, remove the needles, swap the faces and replace the chrome rings onto your original clocks - easy !!