There are so many answers to this question. The oldschool option is as you stated: relocate the leaf springs inboard, mini-tubs, and maybe even roll the fender lips. As for traction aids, the pinion snubber rules. It is the best idea for a Chrysler product using the stock-style suspension. With a limited slip, or locker differential, it is all you need. The Cal-tracs, or any other traction bar, are good, but not recommended by the engineers that built our toys. The reasoning is simple, but sound: the axle tube/center section union is welded, and only partially so. Asking it to take the load of the vehicle's almost full weight, for any amount of time, under the conditions of a dragstrip launch, is asking a lot. If you are traction-limited, or don't have HUGE amounts of torque available, then they work just fine, and do not overload the rear axle at this point. A stroker making the kind of power quoted is not going to be nice to the rear axle. Put as much of your traction control over the pumpkin as you can. With that said, the obvious new-tech option, besides XV's excellent parts, is a 4-link setup. The science is tried and true, and easy to work with. Many systems are almost invisible from inside the car, and will fit your requirements. A 4-link with coil-overs is very adjustable, and will allow a low stance and excellent handling characteristics. The leaf springs of yore are a little less forgiving, and the stance may not be as low as with coil-overs and the 4-link. It's all about the money you want to spend on it, now.