I've had one these monitors and they work ok but not with water injection (it goes blank). I discovered its actually a PC temp monitor that runs on 5v so you could just get a monitor from here:
http://cgi.ebay.co.uk/Digital-Thermo...d=p3286.c0.m14
and then build something that will lower the voltage from 12v to 5v (this is exactly what you get when you pay £35 plus for ebay ACT monitor)
I would have been happy with the ebay jobbie if it worked with Water/meth injection. So in the end i got one from Mike Rainbird. Its expensive but it is a quality item:
HTH
Bobby