what do you mean adjustable, like you want to drive around with a 2" lift but be able to crank it up to 4" on a whim? That's all new to me, not sure why you would even want that. Most adjustable kits are for lowered trucks, for when people make them too low and they would be unusable for daily life like tire rubbing or bottoming out on the pavement, but just gotta have that ****** slammed look, they want to drop it to the ground but then kift it back up when it's time to be an actual vehicle on the street. Not sure why you would want that in a lifted truck, if it's lifted 4" and that's too unruly for you, bringing it down to a 2" lift might have some of the same disadvantages those dumb lowered trucks have, if your truck is lifted 4" and on 35s but you bring it back down because it's "too high" (lol) you will rub for sure. But if your truck is sitting comfortably on 33s, going up to 4" will look silly and not even do that much for you. I'm assuming you're talking airbags or something, there is no kit that I know of for lifted trucks, and even then if you did something custom there would be little to no benefit because simply jacking up a truck with 2" lift on 31s or 33s by an extra 2" will give basically zero benefit offroad because your suspension geometry will be all ****** up. You wouldn't have more flex, simply slightly more ground clearance like a body lift, it would be dumb. The difference between a 2" lift and a 4" lift is huge. With a 2" lift, you don't have to do anything with your driveshafts, don't have to extend brake lines, etc. Your steering angle will need to be adjustred but that's about it. A 4" kit is different, a lot of stuff changes, you'll need to figure out something if you want to keep your sway bar, brake lines may be too short as well as driveshafts, etc. Even if it was "close enough" and you could get away with it, that's such an extreme difference I wouldn't just switch it up at random. If your truck can handle 4" lift, just lift it appropriately and buy the right size tires and be done with it. If you want 2", leave it there. Only thing I can think of is using blocks, get the truck all set up for 4" lift and modify what needs it, then when you want to just pull out the bigger blocks and swap them for ones half the size, slap on some little tires and ennoy having a truck that is two whole inches shorter, but still bigger than stock. Idk man doesn't really make sense to me