well, first off, if you install the multi-leafs, you will raise the rear of the car. seeing that you have mono-leafs, you need to get parts to switch over to the multi's. you'll need new front spring perches,new u-bolts. i think that the lower shock mount might also have to be changed, not sure, it's been awhile. but for performance reasons, people tend to go with the mono's because they give a little better, but for handling, 4 or 5 ply multi's will do great. they also make fiberglass leaf springs which i have heard a lot of people like. i think a company called, "vette products" makes them. so really it's up to you on what you want to do with the car. i used mono-leafs with housing floaters and a ladder bar setup, before i went to a coil over setup. they multi's are a little stiffer on the ride. so really it's up to each individual on what they want.