Wolfgang, really like the diagram. But as far as the gauges themselves, who makes the most accurate ones - or do people just buy originals?
I bought originals and had them professionally restored at Palo Alto Speedo. Teby did the same except he used Hollywood Speedo. They look good. Function well. Very expensive for what you get.
So TRP - here's the million dollar question. You paid a premium and got a premium product. Was it worth it? If you sit the gauges you have side by side with traditional replica gauges such as Beck's or IM's. do you think, "oh yeah, mine definitely look far superior"?
I had N. Hollywood do up a set of 914 gauges for my Spyder project, despite having perfectly serviceable, brand new Chinese repop 356 gauges with the kit, and a set of Brazilian 356 gauges, NOS, on hand.
As explained before, I did it to get the correct sized gauges with the correct faces and ranges (100mm-diameter 250 kph speedo instead of 105mm-diameter and 130 mph; 115 mm diameter, 8k rpm tach instead of 105mm and 6k), because I've gone insane. Every damn detail.
But if you set the gauges out all at once and really look at them, yes: you can easily see the difference in the N. Hollywood gauges. Compared to the Brazilian gauges, the screen is crisper, the background color deeper, and the works are just nicer. Like looking at a very expensive watch next to a Timex.
Setting the Brazilian gauges next to the Chines is like putting the Timex next to a $4 drugstore watch. The Brazilian's buttons are better defined, the screen is a bit better, and so on.
They all look nice, don't get me wrong. No one is going to point and laugh at any of these when checking out your car.
And all these are mechanical: the speedo runs from a cable in the front left hub. The odometer is a cylinder with 10 numbers on gears, not an LCD display. The advantages of this are simplicity, cost, independence from satellites and the fact that they look like they belong in a 60-year-old car.
The disadvantages: plastic gears that break forever the first time you hit the trip reset while rolling (or in 5 years, whichever comes first), occasional broken cables, and in the Chinese/Brazilian case, common (not universal) jumpy tach syndrome, which is reportedly curable with a diode but I don't know. You also can't easily calibrate the speedo to your tire/rim size, which is reportedly a snap with the new GPS gauges.
So: you basically get what you pay for, and in my opinion, the gauge pecking order is.
Best: Original VDO/Porsche gauges (or later repops) rebuilt by Palo Alto or N. Hollywood. About $1,700-$2,500, depending on condition. 3-6-month wait.
Damn Good: Current Beck 356 GPS. About $800! (including the senders) Act Now!
Pretty good: Brazilian VDO repops @about $300 for the set. Talk to me if you want my set.
Good enough, maybe?: Chinese repops. Say $150 for the set.