I actually kind of like the idea of a graphical display better. I find analog instruments a tad easier to read quickly, and you could easily implement 3 or 4 bargraph displays on that, along with absolute numerical values. This would of course require a microcontroller to implement, but that comes with its own set of advantages as well. One would be the ability to program it to send out-of-boundaries conditions (water or oil temp above a maximum, oil pressure below a minimum, etc) and flash the whole display annoyingly to more immediately grab your attention.

Heck, I could plausibly see water temp, oil temp, oil pressure and fuel level all on one gauge, leaving the other two holes in the factory cluster open for manifold pressure and AFR. :D

this would seriously be sweet. I'd love to get my XD-16 as well as real oil pressure and water temp into the cluster... a gauge like this http://www.vgauges.com/catalog/produ...products_id=77 in the fuel gauge location, XD-16 in the water temp location, and relocating the fuel gauge somewhere else would be great, but things would not flow well visually.

And more
remember the display area of the temp gauge in the dash is a 40 mm hole.

100x32 dot matrix
65x32 mm overall
display is 38x14 mm
backlit
http://www.newhavendisplay.com/index...ex&cPath=21_92

http://www.newhavendisplay.com/image...front-NOBL.jpg

Here's a 1x8 char display
overall dimensions 53x24 mm
chars are 7.1 mm tall, total width 33 mm, backlit

http://www.newhavendisplay.com/index...roducts_id=202
http://www.newhavendisplay.com/image...-front_MED.jpg

And a 2x8 (you can display oil temp, water temp, EGT, and kPa :))
http://www.newhavendisplay.com/index...roducts_id=259
Overall 40x35 mm
chars are 5.1 mm tall, 26 mm total width, backlit
http://www.newhavendisplay.com/image...-front_MED.jpg

I just bought one of these and I'm (ever so slowly) writing code to make it work with ms2 and ms3 over serial... It has a speaker, so I'm going to set it up to make obnoxious warning noises if anything gets out of range. Going to run a gm coolant sensor in my pan as oil temp, and not use any aftermarket gauges.

Borrowed the idea from that aussie guy who used the OLED version in his cluster, I'm just going to mount this under my radio... I figure you don't have to look at it all the time if it warns you.

http://www.sparkfun.com/products/10089