i read really good comments about the mgl avionics e1
http://www.mglavionics.com/E1.pdf , you can monitor chts, egts, op , volts, ot , it even has an alarm
in my case, i have a 914 style quad gauge that has a vdo cht ,so decided to go with a Westach 4 pole selector switch , i still have to connect them to my 4 vdo cht senders . (my poor manīs cht monitoring gauge )