I have the rubicon express 3.5" superflex lift. I am also running BFG KM2 35's
Here's my experiences with it.
The reason I bought it
Mainly cost. So far it's been pretty decent in that regard. It comes with an adjustable track bar (which works fine), a rear track bar bracket (which seems strong enough, and much stronger than some others I have seen, as it ties into the Lower control arm bracket too), springs obviously, Fixed lower control arms, adjustable upper control arms, brake lines, sway bar disconnects, and bump stops. It seemed to have everything I needed (except shocks but you buy those separately on most kits anyway)
Breakdown of each part
1. Adjustable front track bar. The bushing at the axle mount is getting worn as there's not an entire wall of metal for the bushing to sit against in the bracket, so the upper right bit of bushing is getting gradually eaten away by the edge of the axle mount. This so far hasn't caused any problems. The frame end I just have to grease every now and again. A dab of loctite on the jam nut will keep it from coming loose, I have had that happen
2. Rear track bar bracket. Ties into LCA mount at the axle and has a crush sleeve inserted into the factory track bar bracket, works well enough.
3. lower control arms. Not adjustable, heavier than factory control arms and seemed strong enough for what I do right now, haven't broken anything and the finish is holding up fine on them. You need to grease these somewhat regularly, they have grease zerks.
4. Upper control arms. Adjustable, hold up fine just like the lowers. You also need to grease these, they have grease zerks.
5. Sway bar disconnects. Also have held up fine, but I cannot take the bolt off the top as theyre both seized, I torqued them to spec so :idontknow: These have grease zerks as well at the top, and a nice little holder for them when it's disconnected to attach to and hold the sway bar up and out of the way, I like that little detail.
Now, so far everything has performed as expected and seemed fine for the most part sans a few niggles.
How does it ride?
So, here's where I want to be as critical as possible. It's VERY stiff. I have it paired with the bilstein 5100's and the ride is quite stiff, going over a speed bump will pretty much get air and get a very harsh front jounce, definitely "worse" (IMO) than factory suspension with rubicon shocks, which would glide over speed bumps perfectly. There's a lot of shock transfer to the cab. It's also noisier, if you don't keep up on the greasing then you'll get squeaks, and I get squeaks anyway with the suspension in a droop that I didn't with the factory suspension. I am running with a heavier evo tire carrier in the back now and that helped the stiffer ride, but with a factory bumper in front still and no winch the front is not very forgiving to your kidneys.
The lift itself
I got a lot more than i expected. In fact when I didn't have the evo tire carrier it looked kinda funny sitting on 35's. When I had the top and doors off it would sit awkwardly high on 35's. Now that I have the tire carrier the rear sits just fine I think, but again, my front is still higher than I want. Keep in mind, I have factory uncut flares. If you plan to cut your flares you're going to have the most awkward looking ride with 35's
Problems
I've already mentioned the front track bar bushing, seized bolts on the swaybar links, and quite harsh ride, but I want to bring to light a bigger issue. The provided bump stops in the kit are not long enough in the front. The springs will bottom out and completely collapse and go solid before you're completely compressing the bump stop foam. This means bottoming out is 1. Not as predictable as a feeling, 2. Hard on the springs, and 3. The shocks for a 2-4" lift (listed on sites as general shocks you buy when looking at JK specific ones) will actually bottom out as well and also act as a bump stop! This will destroy your shocks in no time at all. I thought I had a picture of it flexed and showing solid coils, but alas I don't seem to have it. I have personally witnessed it though.
The other BIG problem, is my front driveshaft, unless you want to replace it, get a different kit. My slip shaft boot is completely torn off right now, and the CV joint is at a very extreme angle. It's on its way out and going to be busted any time now. The instructions state you have to remove the skid plate to make clearance for your driveshaft, but if you do that you'll definitely kill your CV boot and destroy it there, if you don't take it out, you'll be notching the skid plate when you fully extend and be rubbing the driveshaft on it, thus tearing the slip shaft boot and eventually cutting your driveshaft in half probably :cheesy: It's a lose lose situation. I opted to keep my factory skid plate because I don't want to remove protection that was already there just to destroy my driveshaft differently...
Also, another thing I wanted to mention was my kit came with 2 right rear braided brake lines. I contacted them and they didn't offer to send out the left one, they actually said "it'll still work fine", and it does, but there's not as much clearance against my tire as there should be. If I was running more backspacing I'd be rubbing the lines regularly. I was not happy that they sent the wrong part and essentially said "deal with it".
Overall, It's an okay lift for the price, but it has its issues. I have also personally driven (a lot) a 2 door JK with a 4" rancho lift (which actually sits lower than my rubicon express 3.5" superflex! [but he also has full steel bumpers]), with adjustable rancho 9000XL shocks, and the difference in ride is night and day, not nearly as harsh as the rubicon express kit. All that being said, would I buy this kit again? Probably not, I am not too unhappy with it, but there are better choices. I could probably fit 37's on this kit with minimal cutting. I can't imagine how tall the 4.5" rubicon express superflex kit actually sits :crazyeyes:
Hope that bit of info helped your decision making, I dunno.