Update - Now installed
I installed the 360Infinite HUD as shown in this thread, $80 on eBay.
The toughest part was taking off the binnacle. Once off, all the wires I needed were within the gauge area and it was very easy to install. The speed sensor wire (orange/brown) is a common type mail/female singe wire connector so it was easy to make a connector that Y’d off without cutting wires. I tapped in to the RPM white/slate wire by stripping its shielding (no cutting). Power comes from the rear defrost switch which I tapped in to from stripping the shielding off the wires. I am also using it as the switch to power the HUD on/off. I unplugged the defrost wire on the window, I have never used it anyway and if I need it I just plug it back on at the window.
The wires come out from under the front of the binnacle and I used some gentle two-way tape to secure it in place on the dash between the binnacle and the windshield right below the serial number plate. The system dims at night and is bright enough in sunlight that I don't need the mirrored film it comes with.
The Lotus dash is low (I am 6’2”), dark and has small text (I am getting old) so I can't read my speed (it is MPH). Also when I am driving hard, I am not looking down at the gauges to see the RPM and tend to hit the rev limiter often. The Heads Up Display projects onto the windshield in my line of view just above he number plate, yet low enough not to interfere with road vision.
The white circular dial is RPM and when it turns red I need to shift. On the right is speed in KPH (Canada), it turns red at 120 KPH (adjustable). I calibrated speed with my GPS at 40 KPH and at 90 KPH so I am certain the HUD is accurate. It is perfect and I love it!
The clear LED (green) in the foreground is the car alarm indicator.