When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I have used the "Wired" UltraGauge in my Mustangs and Miatas for a few years. Its simple and cheap at $70 but lets you view up to 8 gauges at once. Not good to use as a tachometer due to a bit of lag but the other gauges are useful.
They have a new wireless version which can be viewed on a smartphone or tablet but I have no experience with this version.