i just put on my 05 LJ the rough country 3.25 progressive lift with the 2.2 shocks, quick disco's, and the premium steering stabilizer. all came to my house for $476 took it out and rides great on road and off, will give updates as time goes by.
here I thought we were going to be discussing two post vs 4 post lifts. hmm.
31's don't "need" any lift, but if you want to lift it you are on the right track. if you are just after the "look". then get a BB, and go on with your day. Its an easy DIY, but if you insist on paying someone hold onto your wallet, as it will magically lighten, and may try to fly into outer orbit.
I'm being slightly sarcastic, but the point is still true. If you have any moderately mechanical friends you can do it in an afternoon (or morning if you prefer).
Just make sure to set the Toe after wards (this will be more difficult than installing a BB, however many people less intelligent than you have done it.)
I just purchased an OME 2.5 inch lift which comes with very nice shocks, according to all the reading I have done, 4 springs that match the shocks that are custom for the model and weight you will have, transfer case lowering material that you may not need and if you do you can use longer hardened bolts for a lot less money, bump stops for the rear and the track bar extension bracket. Total bill was around $800 but you can knock off $80 if you don't use the transfer case kit. Installion will run around $300 and you can align the front wheels yourself and save another $75. Save even more money if you have the knowledge and a buddy to help with the installation. Hope this helps with your questions.
I just got 2.25" BB with Rancho RX9000xl Shocks... ANd let me tell you that those shocks may have cost me 75$ each, but it was well worth it. They adjust 9 ways, soft ride to hard ride.. But anyways, i like the look with 2.25" BB with 31x10.50 tires. I got the BB for 85$ shipped and the shocks were 300$ all together, but you don't need to get expensive shocks like i did.
Here's where i bought my BB's: 4 Wheel Customs - TJ/LJ/Rubicon 2.25" Complete Budget Boost Kits
After you install them, Go on ( YouTube as someone already said) very easy to do, you are going to feel you TJ drive stiffer than it already does, because most likely your shocks aren't big enough for the lift. Get 4 new shocks like Skyjacker hydro's 40$ (each) that extend long enough for the lift and collapse good enough too.
My shocks extend 23" and Collapse 13".
If the current spring rate is adequate, go BB with good shocks. Use the money you save on springs to chase down the nearly inevitable driveline vibrations.
I've know that everybody loves to say that you don't need to address the driveline with 2" of lift, but hell, I had more vibrations than I wanted at 0" lift. 1" lift (result of swapping to a Ford 8.8" axle), super-short SYE, and a nice long driveshaft, and life is better!