I stand behind K&N for intakes. I've had a K&N on both of my lasts Jeep's and love them. Their website says it can give a WJ's V8 13+hp if I remember correctly.
Yes...I know about exhaust...and its not number 20 Paul...its only 14...LOL!!!
If you want ridiculously LOUD, get a PowerStick from ClassicCambered.com. Super loud, raw tone. Search hb1213 on youtube, and you can hear it.
There are no headers of WJ's. Unless you fab some up, you're stuck with the stockers...