Air fuel gauge = useless, unless it's a wideband.
You should have a boost gauge if you're planning to turn up the boost, and I dont know about any temp gauge, I think they're all useless, because things can go wrong at xxx degrees or xxxx degrees, it just depends on your car... my opinion atleast. Plus your engine should throw the cell if anything goes wrong in that department - I know durango's do
If anything get an EGT and install it on your up-pipe during the install.