manual swap is the best solution. Why would you not want a manual for the freeway? I would think a manual used for daily traffic would be more of a PITA. You can physically fit the 5 and 6 speed up to the engine but they are nearly impossible to run electronically w/o the factory ecu (which cannot be used w/ a 96 motor. You can build the 4 speed with a valve body upgrade + upgraded clutch packs and higher stall tq converter to cut the majority of the shift lag but at the end of the day the heavy tq converor will always sap 20% of BHP. Also, with a built auto, it will shift MUCH faster than any manual swap. There is always a compromise but this doesnt mean your out of options, it just comes down to personal preference. BTW, a built auto would end up costing the same as a manual conversion so price wise both options cost the same.
Hope this helps some