hmm interesting opinions in here.
Stay away from K&N? i have one. love it. clean it every oil change and they last for along time.
and how can you tell someone to never use 4wd on pavement without having knowledge as to what TC they have? If you have a 242 with Full-Time then by all means. Use it!
I agree with the exhaust statements, Open it up a bit. 2-2.5" pipe. good cat/good muffler Make sure your Exhaust manifold is solid with no cracks.
If it has OEM original mounts, Replace them.
Flush all your fluids, Check your tire pressure.
good tune-up will go along way.