Best use of spare instrument space?

UPDATE: I've decided that I need a combo EGT/CHT emgine monitor, and that I will buy it from someone other than JPI. I did a little research and it didn't take long to find their abysmal reputation for customer support and some of their more heavy-handed legal tactics. I have no patience for that kind of thing, so will look elsewhere for what is in essence a commodity product. It amazes me that a company making a product that is easily available from a competitor at the same price point doesn't realize (or care) what a bad reputation can do to them.

Original post:

Since I moved by mag compass to a new location in the panel, I have an empty 3 1/8" instrument hole to fill. My first thought was to put in a g-meter, but given the type of flying that I do, there's no real need for it.

One need I do have, however, is in the realm of engine management. I do not have any temperature gauges whatsoever, other than oil temp which is nearly a constant anyway.

The two possible engine temp gauges under consideration are either cylinder head temp (CHT) or engine exhaust temp (EGT). My understanding (and please, chime in with a comment if you disagree) is that EGT is more useful in determining the best mixture to set than CHT. Assistance in setting the appropriate mixture is primarily what I'm after, so unless a strong counter argument can be made for monitoring CHT instead, I'm planning on installing an EGT gauge.

Of course, if I were willing to spend the money, I could have both, but graphic engine monitors that display both EGT and CHT are pretty expensive. If I choose to do only EGT, it will be quite a bit cheaper, and I'm not convinced that I need both. Again, chime in if you disagree.

In any event, if I go with EGT, I want it on every cylinder. Leaning based on the EGT of a single cylinder seems pretty risky.

So, with all that said, here is the gauge I'm looking at:



With all four probes, it's going to be nearly $400. A graphical engine monitor that provided both 4 cylinder EGT and CHT is about $1000 more:

http://www.aircraftspruce.com/catalog/inpages/gem1.php

I think I will get what I need from the lower cost alternative, but I can still be persuaded.

UPDATE:

Another option:



I'll have to measure, but I think I have the required space behind the panel for it to fit. But at $2300 for the display and probes, it definitely blows the budget all to heck.

I looked at the JPI and EI units, but they are all 2-1/4" units, and I'd really like to completely fill the 3-1/8" hole. I'm not ruling out one of the smaller units, though, as I imagine I'd get used to it pretty quickly.