I had to bore out an area just slightly smaller than the footprint of the housing that you see in the pic. A template helped - it was a pretty unsavory experience though, having to remove that much metal from an otherwise stock SVT. The result was worth it. The colour is virtually bang on with the other indicators - the only difference is that the LEDs light up a fraction of a second quicker than the front and rear indicators.
Did I mention they're directional - you can see from the pic that they point rearward about 15 degrees
