Cross drilled or slotted are a waste of time and money IMO, I had them for a while and due to circumstances, I swapped back to a stock rotor and pads, the braking was great with the stock set-up compared to the cross-drilled.
A decent up grade is to use the '92 to '94 front brakes, they will bolt on in place of your existing set-up now.
You will need the following:
'92 to '94 J-body spindles
'92 to '94 rotors
'92 to '94 calipers.
Now the easiest way to install them is to put the left side '92 to '94 spindles on the right side and vise versa, since this will keep the caliper at the front of the spindle and allow you to use your existing flex line. To use them on the "proper" sides would require new hard lines from the master cylinder to the wheels, they are bent differently at the wheel. Use the left caliper on the left, right caliper on the right, this keeps the bleeders in proper orientation.
Another very good upgrade is braided brake lines, they expand much less than the OEM rubber lines, and will give you a firmer brake pedal and better fluid transfer to the caliper.
Rear disc, well there are so many ways to do this, that there is no one "right way" to do this, I mean there are many combinations of parts to choose from. I chose a complete set-up from a different car, a Chrysler in fact, this gave me a disc main brake and a separate drum type emergency/parking brake, but since plans have changed with The Raven, I am now selling this already modified rear disc axle, if you're interested PM or e-mail me.