I've got several gauges in the boxes. Just waiting for some free time to install them. I plan on putting boost and EGT in an A-pillar pod and trans temp, water temp, oil pressure, and voltage in an overhead quad pod. The quad pod may or may not fit and will probably require modification to fit.
Locations for senders are not jumping out at me. When it comes time to start installing things I'll probably park the Jeep in the garage and drive my truck. This way I can take my time and start disassembling the engine compartment to see what I can find. Here is my speculation...
EGT - I'll probably end up tapping the exhaust manifold. The easiest way might be from the bottom, or maybe removing some things to get to the top. An idea I had was disconnecting the EGR port and creating a fitting to go into the EGR hole that would hold the EGT sender. I don't know how feasible that is though. Don't know if the EGR would still function without error codes or problems.
Boost - I'm planning to put the sender in where the intake tube goes into the intake manifold. This way I can get the shavings out. If the metal is too thin to tap (or I screw it up) I bought some drain plug kits I can use.
Oil pressure - Probably 'T' into the factory oil pressure sensor. I've been considering integrating the oil pressure sensor with a bypass oil filter setup. There seems to be a plug on the front of the oil pan that could be used but it's only about 1" from the front axle assembly so things would be tight. I'm also not sure what kind of threads are on that plug or the factory oil sender. I'm hoping for normal NPT but you never know.
Trans temp - I have a remote filter with a temperature probe port so I'm using that.
http://liberty.eurekaboy.com/transfilter.htm
Water temp - Have no clue on that one. I'd like to find a drain plug in the block but so far I haven't. I haven't found any plugs in the manifold or thermostat housing but I haven't looked real hard yet.
Voltage - The only easy gauge in the bunch.
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My Jeep Liberty pageORM, air filter mod, and less restrictive exhaust has increased my 'everyday' driving 3 mpg.