new gauges

I making a place for two or three more gauges, i am thinking that volt, and fuel pressure are the most useful for me. Any body use a pyrometer in their car? What about trans temp? Aside from just being nice to have the data, are these last two really that important to have? I have water temp and oil pressure now in an a pillar. these new ones are going in a cd delete panel from FL5.0.

Thanks!