I've been running the 180 tstat off a 5.9 for a little while now and have noticed no ill effects other than it runs a bit cooler.

 

I have the AirRaid intake system, Poweraid TBS ... which didnt do much other than give my truck a nice swoosh sounds when throttled.
I did see improvement in low end torque with the addition of the Gibson headers and Flowmaster exhaust.
To be honest I didnt notice a big improvement with the Superships Flashpaq tuner, unless I set the economy mode.

 

One should not buy a superchips for mileage improvements only. If thats your only reason, skip it.

 

i was averaging about 11-12 mpg running 93 cause i pull with my truck then i got a superchips cortex 3950 running the 91 performance tune notice a huge difference and i now average 15-17 on the performance tune. it will quickly pay itself off in my books with the mileage increase. and with the cortex comes a 2 year power train warranty which gives me a little piece of mind