I did contact them a couple of weeks ago regarding their differential drop brackets but they did not want to give me any measurement information and told me that their brackets would not fit my FTS lift bracketry. I'm still not convinced though. I'm not a suspension expert but I'm thinking they should work just fine.
so the problem is, kind of what I was just saying above, not that it "wont work" but as the drop bracket changes, the spindle needs to change with it. So if your bracket is 6" and the spindle is designed to work with that, you change the bracket to 8 or 10 inches, now what about the spindle? Well it might still work, but your balljoint is not going to be where it should be.
Catastrophic problem? ehh, maybe not depending on the variables but no one is going to endorse that from a business stand point.
if you notice, some of the companies sell aftermarket UCA that 'allow for better angles'. Same issue, other direction. Instead of changing the spindle, change the balljoint location and try to correct for some of that change. that's kind of why you see it advertised as something like stage 1 4 inch lift (basic kit, no preload spacers), stage 2 6 inch kit w/ preload spacer and UCA. Instead of making two separate lifts, stretching the 4 to 6 and readjusting the balljoint. The cheaper, less correct way to do this.
The thing about Independent suspensions, when one thing changes, everything else needs to change in relation to it. With a solid axle setup, the same thing is true but its MUCH less sensitive to change.
Using the 2500HD as an example, theres a reason why some kits are 2500 dolalrs and some are 4-5k dollars. While cognito and CST do charge for their name, most of that excess cost is based on the more extensive development required to make a 'better lift'.
