This Add-a-Leaf (AOL) kit is the perfect answer for border-line suspension concerns you might have when considering load carrying, towing, or just plain "attitude" of a new vehicle. But this would also do wonders for an older vehicle suffering from a bit of sag, or anticipating heavier duty requirements ahead. My application was on a 2017 TRD Sport 4x4 Tacoma. I wanted to pull my utility trailer, boat trailer, or haul medium duty loads without any compromise to the OEM ride or handling characteristics. That is exactly what I got when I installed this kit, and about a 2" lift in the rear as well.The before and after performance was impressive to me, because the kit made the truck handle, respond, corner, and stop the same as if no loads were present. Whereas before, some sagging in the rear and trailer sway were possible under certain conditions. Now let me say that I don't drive or test the vehicle for loading or towing that exceeds the OEM ratings. But I am very confident that the truck can EASILY perform all of my required duties up to AND including the maximums certified on the stickers.Installation was fairly basic. Working on one side of the vehicle, at a time - The two sets of OEM leaf spring stack U-bolts at the axle tube have to be removed, just to insert the "helper leaf" on top of the stack - sliding it under the bump stops, then re-tightening everything to proper torque - just as before. Then a U-bolt and its retaining bar and hardware are added on each end of the helper leaf, on both sides of the vehicle, tightening them down - and even adjusting the ride height if you desire to do so when completed. The nuts require a 17mm wrench or socket tool for their adjustment and Hellwig provides double-nuts for the rears, just to prevent your adjustment from loosening up during the months ahead. A special "bar" (for the U-bold retainer) is provided for the driver-side setup to provide added clearance, but was not an issue on my truck. But it was made to satisfy either application, (painted black for its identification as being "different").My kit required some contact with Hellwig customer service. The reasons were so minor, I am not going to write them here. But I mention it only to convey the superb service they provide there. I had them sent me some extra hardware - and they did so TWICE, at no charge, and rather quickly via UPS. They were fast to respond and asked no questions. This experience was as good as it gets considering the product, company, and service all seem to be of the highest standards. I recommend them for those reasons.