A while back we bought one of these shiftlights to fit to our own car. After they saw it all our friends wanted them and asked us to import some for them too. Then their friends saw the and wanted them too. So now we're a UK dealer for the Shift-I shiftlight
With only 3 wires to connect (power, ground and tacho) and a pair of buttons on the front panel to set the shift points a sequential shiftlight doesn't get any easier to install than this.