I went with GPS speedometer on my 53. It's simple and effective. I went with DD gauges. They also Bluetooth to my phone. That's nice when working under the hood. I have a Frankland Quick Change rear end with 128 possible gear ratios so it was a no brainer for me. It also gives me 0-60, 1/8 mile and 1/4 mile times. It updates something like 100 times a second and has memory for loss of signal. GPS is the way to go. It also powers my cruize control.
