I have a 3" body lift on my tj. It was on there when I bought it and I haven't gotten around to buying a smaller one. The only pro I can think of is the clearance, not just to run larger tires but you can reach some other things very easily such as rear upper shock mount bolts from the top. In my case, there is also enough room between the frame and the body to get an angle grinder in most spots so I can get rid of some rust and repaint the frame.
For the negatives, it looks kind of dumb. I also had to remove the shifter boot or I have trouble shifting into 2nd 5th and reverse. The transfer case linkage is also hard to get adjusted properly without a cable shifter. I have to be careful shifting into 4h and sometimes I can't use 4low.
Mine has a bracket that lowers the radiator 3" so you don't need to mess with the fan shroud. I also don't have any problems with the fuel filler or steering like others have mentioned and I haven't noticed any damage done to the body mounts from the tall spacers.
I do plan to remove it and use a smaller bl. If I had a Novak cable shifter and a flat skid to raise the transmission up some so the shifter cleared the console better it would help a lot. If you can deal with those things and like the looks then get one.
I purchased my 90 YJ with a suspension lift and a 3" BL. I have no plans to change either.
It's nice to hear someone (above) pipe up with some facts. Most of the folks, when commenting on 3" BL's, give _their_ opinion that "they" don't like the looks (not necessarily bad, just not overly helpful).
So, for some facts as I see it:
- "They say" it is bad for the body mounts. I have yet to see any deformation or issue with my mounts. While it could happen, it has not for my vehicle. Should it deform my body mounts in an accident, I don't care at that point, as there likely are larger issues to deal with.
- The body is moved up/away from the top of the tires w/o having to trim the body.
- The body is moved up/away from the top of the tires w/o having to install a taller suspension lift.
- The body is moved up/away from the top of the tires with less "bad angle" on the rear driveshaft from a larger suspension lift.
- The 3" BL vehicle, vs. one that attains the same body to top of tire clearance via suspension lift, has a lower center of gravity (a nice item to have for hose marginal tip situations).
- It is nice being able to access some vehicle areas, easily, by having that extra gap between the frame and body.
- Radiator / Shift levers / Fuel fill items are not guaranteed to be "at-issue" because of the lift. If they are, change can be made to remove the issue (I have no issues on mine - and I use stock fuel fill hoses).
Now, there is some functional limit to how high of a body lift you can go. The two I see deal with the body mount deformation and shifting. Taken to an extreme, say a two foot body mount, would move the body up on the shift lever enough that the shifter levers would hit the factory shift lever hole before completing the throw into gear. Specific modifications would be needed to likely move the pivot points of the levers. The "lever effect" of the mass of the body could well cause the body-to-lift to "rotate" and deform the body then the vehicle changes speed or direction quick enough. A fix for this lever effect would be to have a body lift that was of a larger diameter to get the body-to-lift "rotate" forces back in line with a stock or small lift setup.
I'm curious to hear more fact on why it's so bad. I mostly hear "opinion" and that's not helpful. I do agree, there is a physical limit but, to me, 3" isn't over the limit.
I can't think of a single 'pro' in favor of a 3" body lift. Not to mention it's actually easier to install a 3" suspension lift. There is a lot of work involved in getting everything working properly with a 3" body lift... t-case & transmission shifters, gasoline hoses, etc. Plus I personally just feel a 3" body lift looks like crap.
My jeep had a 3" BL on it when I bought it. It was done right, the steering was adjusted, along with the fan shroud. It was not unsafe at all. I have since modded my jeep a little more, and am removing the BL and replacing it with a 1" BL. Personally I would not do it, but not for the reasons stated above. You will get more function from a suspension lift. I would recommend a 2" Suspension lift, with a 1.25 BL. Put on some high clearance fenders, a tummy tuck and call it good. Here is a pic of mine. I also have a cable shifter, and a tummy tuck.