A good cheaper alternative to the scangauge is the Ultragauge. It is cheaper then Scangauge (It cost me about $78($69 +7.95) ) and has a bigger screen then SGII which is good in the sunlight and also good in the night
It is a company based in the USA and I got my unit in 3 days
I wanted an OBDII gauge for my XB because the thing has only a dummy light and not a temp gauge(they removed that feature for a clock

in the 2011 and 2012 Scion XB) and saw $150 for the SGII to be excessive for what I was looking for
Here is the link
http://www.ultra-gauge.com/ultragauge/index.htm" onclick="window.open(this.href);return false;
Here is how it came packed
It is no bigger then a standard size business card
Here are some pics of the Ultragauge in action in my XB. It has the capability to display 7 pages of 8 gauges. I only have the battery and temp gauges set up because that is all i was looking for.
Test hookup and off center
As it is just for this car, I have it running down to the OBDII connector through the gap in the steering wheel and the dash
It has a side mounted wire to connect to the OBDII connector so as to not be bumped by the drivers legs
At night:
The unit retains its memory of your settings and shuts off when the ignition is turned off and the door is open so as to not drain your battery.