Banks, ISSPRO and AutoMeter are all good guages. EGT guages are not cheap; plan ~$175 for the parts.
Also, the install is interesting. You have to find a location to drill & install the probe into the exhaust stream, as close to a cylinder port as practical. Obviously in a cylinder would be the best up-to-the-nanosecond reading, but problematic to drill & install a probe there
Just outside the cylinder gives a pretty good reading. Downstream a ways allows some drop in temp, so you don't get accurate in-the-cylinder reading, tho you can make useful comparative readings w/more remote mountings. I prefer just after the cast exhaust header, as that reduces influence of changes in ambient temps that reduce readings more in winter than in summer; I don't have to make any seasonal adjustments mentally (as that is frequently a source of much forgetfulness & error; just ask the woman that feeds me, her name is, er, well, uh... was it Judy?
). That location also has complications, though of a more manageable type- if you just drill exhaust tube in place, shavings fall inside & get blown thru turbo, into intercooler. So best to remove the exhaust pipe to drill. Some purists remove & drill/tap the cast exhaust header; they have my admiration.
Mike makes the point that shut-down is an important point in time regarding
EGT & turbo-diesels. For those not in the know on that point, the turbo is oil cooled, so if it is passing 1100 degree exhaust (climbing a mountain), and you pull over and shut down, you will cook the oil that was passing thru the turbo but is now stationary within it (motor oil burns somewhere shortly above ~240 degrees). Long idling has been shown to be n.g. for diesels (truckers do it to keep AC & other stuff going), but a coupla minutes idling after a long pull & before shutdown is in order to keep the turbo oil passages from choking up w/burnt oil residue.
Maybe WRV will install EGT guages @ Homecoming as one of the 3 things?