There's a 4-character minimum on searches. Get around it by searching on IRS* There are at least 2 threads here from not long ago dealing with the swap into a fox-body and if I recall correctly one of them was a 4-eye like an 84 or 86 or something.
Opinions are mixed. I happen to believe you would be better off working with the solid axle unless you were dying to be different. You have 3 solid commercially-available options for the stick axle, Griggs or Maximum Motorsports Torque Arm & Panhard, Evolution Motorsports tri-link, and the Steeda 5-link. All of them are tried & true in fox bodies to varying degrees, the least proven being the EM tri-link. But read up on the IRS swap, the things you have to do to the factory IRS to make it worthwhile, and the resulting weight and performance limitations. I'm not bagging on the IRS, it's arguably better than the stock 4-link, but may not represent an effective upgrade for your car given what else is available.