The factory 4-link is not that good, arms are to short, brackets rip off easy. That is why a lot of people go to leafs on a 2nd gen runner.
I see. Well, I was not planning on lifting this truck, and I was going for more of a smooth ride over off-roading. I assumed the 4 link would be a smoother riding set up than the factory toy leaf springs. I am looking for a frame for the 90, and I didn't even consider the 4runner frame. Then someone brought it to my attention, so I thought about it a bit, and figured coils would be smoother than leafs. If it really is an extremely weak design, I probably wont do it and just keep searching for an ifs truck frame. Although I do not plan on offroading this truck in the same way as the 85, I was planning on making it a fun dd/desert type truck, so jumping is in the plans. I am guessing the stock 4 link is not up to that task?