I'm thinking of installing a Performance chip on the QX any Pro's and Con's?

Lots of chips out there. Do a search on "performance chip" in this forum and in Club Titan and your head will be spinning from all the results. This is one of the more recent.
http://www.clubarmada.com/forums/showthread.php?t=6200&highlight=Chip

Good. Uprev and Stillen are the two I would look at.

I installed the Unichip on my spyder and removed it after about 2 weeks. There were definitely power gains, but my car never idled correctly... this was with a pretuned map specific to my modifications. Lots of people have had very positive results w/them, but not the cheap ones you see on e-bay... a good chip will cost anywhere from $400-$900.

I think the best bang for the buck is the UpRev tune. You can have three different maps, and select between them whenever you want. No added hardware, no wiring.
I have a stock map, performance map and a valet map. The UpRev tune can reset your rev limiter (but that really isn't needed) and the speed limiter.
For best results you need to go th Austin for a custom tune.
The cost is less than the generic piggy back like the Stillen.
I'm not saying there is anything wrong with the Stillen; we don't know yet since it is still not shipping.
From my avatar you can see the results of the UpRev tune on my Armada. I have the Volant CAI, Gibson single, Airaid TBS, Active tuning grounding kit.
I don't know of another NA Armada performing any better than my 14.47 1/4 and 5.81 0-60.