I already have an APEXi exh. gas temperature gauge. I plan on purchasing two more gauges for additional vital monitoring but I can't make up my mind for the life of me. My choices have been between oil temp., oil pressure, and water temp. Which one would you consider more......vital?

 

OIL Pressure, without a doubt should be there. with water temp being the next guage I would put in, followed by oil temp.