Where are you putting the gauges? In the dash, on the pillar, in the glove box or some other non-standard location? Pillar mounts have their particular sizes due to the size of the gauge holder. Dash mounting limits the size due to space. Glove box is the same. Standard size is about 2" or 52mm or so. Price is relative. How much do you want to spend on a particular name brand? Is an off brand ok? Do you want and or need a particular illumination color or background? You should check your local speed shop.

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