GAUGES...Under dash or on top of dash

I agree with straightlinespeed. Any of the gauge sets I've had mounted below the dash tended to go ignored until we had problems. I suppose it would work better if combined with warning lights in your view that were set to illuminate before it's too late to matter.

On top of the dash can get into your line of sight if they're large or if you sit low in the seat. I never cared for the big 5" tachs on top of the dash in anything but a race car.

The original cluster area is the ideal if you can pull it off.