What would be the pros and cons of adding a AFE Stage 2 Cold air intake & Flowmaster 50 delta flow?

Has anyone added an AFE Stage 2 Cold air intake and than removed it and went back to stock? If yes, why?

As for adding an entire FLowmaster 50 Delta Flow Force II Kit, someone said that the Jeep's pipes are already stainless steel and no point in changing them... Which parts of the exhaust system would you change than? The tailpipe and the muffler?

Also, which of these cons would still apply to the newer AFE Stage 2 Cold Air Intake: (Taken from a post written in 2008)

So What Do We Know about Cold Air Intakes:
Pros:
1. Eliminates stock airbox (may be necessary for custom fenders)
2. Improved HP and TQ by about 2-3% at ~4500rpm (Engine max: 5200rpm).

Cons:
1. Expensive - brand name kits cost around $150+
2. Cleaning - open element filter is exposed to much more dirt, mud, dust and debris from engine compartment.
3. Thin film of dust typically passing through filter, thus the engine is exposed to this dust.
4. Oiled filter versions further attract dust, dirt and debris.
5. Due to inadequete filtering, a Outwears Pre-filter, or similar filter sock is required, further adding to cost.
6. Requires frequent cleaning due to dirty environment - typical cleaning kit costs $20+.
7. Increases risk of hydrolocking - exposed element can suck water into engine easily.
8. Noise - annoying "sucking" noise can be heard, sometimes associated with a loud whistle.
9. Dirty filter can cause rough and/or high idle.

 

The WK is so quiet and civilised why would you want to make it less so.
The stock intake already takes its air from outside, all them cone shaped things do is screw things up.