I'll list my beef with their LNG arm kit. I ran the 3" LCG long arm lift, with longer Rock Krawler heim jointed sway bar links, because the provided Teraflex links wear out quick, but that's another issue.
1. The flex joints do not provide enough misalignment. When flexing, the ball inside the flex joint bottoms out on the housing. At that point, a strong rotational force is transmitted through the entire control arm, especially the lowers, to the frames ode bushings that DO NOT handle rotational force well at all, and will behind clanging and actually start pulling out of the control arm.
2. There is a significant loss of ground clearance due to how low the lower control arm frame side mounts hang. I constantly hng up on rick with these low hanging mounts.
3. The mounts are weak. I had one crack, and rip off a portion of the frame with the left over part of the mount. My kit was installed by a certified aircraft welder, with over 12 years of experience welding aircraft structures. My front control arm mounts were getting stress cracks all over the area where the lugs that the control arm joints attach to. Again I suspect from reaching max misalignment and transitioning the rotational force to the control arm mounts. This was nowhere near the welds on the front mounts.
4. The provided "monster" front track bar snapped in two on me, three separate times. I'm told they changed the design, but after those failures I lost test in such a critical component and ran a stock track bar instead.
5. The springs were very stiff. And the base 9550 shocks are kind of stiff as well, and three of them started leak g within 20k miles of use.
6. The 9550 steering stabilizer would leak out all of its fluid just about bi monthly. I ended up giving up on replacing it, and just left it on there. My alignment settings were good enough I didn't notice it much or need a steering stabilizer.
I could not imagine how fast you would blow through flex joints and bushings with coil overs like the Evo bolt on coil overs. I ran the Evo Rock Star rear lower control arm mounts/skids, which gave me about an inch more droop, and made me rip through frame side bushings. My shocks are what limited my droop, and it was not enough to unseat the springs or anything, so it should be what I consider with the design limits of the system.
Teraflex was quick yo replace all of my failed parts without issue, shipping included. But a lot of good that does you with a $700 tow bill, or limping down the road with a winch cable and about. 6 ratchet straps making up hour front track bar at a 30-35 mpg hop speed before severe death wobble ensued.
This isn't just here-say and bashing. I've got pics to show the failures I had.
This is what failed first, NOT the weld. Limping it back to the parking area at Rausch Creek caused the failure at the weld. I caught this when hearing a loud clanging noise on the trail, found this section broken.
Clean snap.
It did flex well.
Note the very low frame side control arm mounts.
The kit new.
I can't find the pics of my broken Teraflex Monster track bar, but it looked EXACTLY like this.