WK 4" Superlift @ 50k miles
I've had the 4" Superlift on my WK for about 50 k miles, I also rock crawl it fairly aggressively and this is my first IFS wheeler (I'm more used to solid axles and associated componetry).
To make a long story short: I've been trying to fix some clunking up front and started replacing components on the lower control arms (including labor-intensive ball joint replacement). I've finally realized that all bushings and the ball joints on the arms are bad and I should have just replaced the entire arms (which come with components pre-installed) instead of replacing piecemeal.
Also, as a precaution I had a mechanic replace the inner tie rods on the steering rack (in 2007 I was at Grand Slam West in Moab, driving Jeep's Superlifted WK test mule with 50 k miles and I pretzeled an inner tie rod simply climbing a rock, so I figured these things only last 50 k miles when wheeled aggressively). The mechanic said both tie rods were totally shot and that the rack itself was leaking.
So, at 50 k miles, I'm replacing my lower control arms (and all associated components), upper ball joints, steering rack and my weakening Bilstein struts. I bought the new components from O'Reilly's which has a lifetime warranty. I full expect this to happen again at 100k (I truly think that hard wheeling brutalizes the components on this setup) so while I'll have to pay for labor, I shouldn't have to pay for parts again.
When the front isn't clunking, I still love the ride of my WK both on pavement and on trail. I have no regrets but wanted to let people know what to expect with this type of setup.
And, if you have a similar setup and you start getting clunking up front, don't make the same mistake I did - don't replace individual lower control arm components, just buy brand new lower control arms with pre-installed components, you'll save money in the long term.