I'm going through the same questions...have the stock box rebuilt and add fast ratio arms or get a Firm Feel manual box with the faster ratio guts or a Flaming River box.
Leaning towards a FR box, cheaper (500 @ Speedway vs 675 for FF with column adapter) and a bolt in. Some say they are hard to steer at low speeds with bigger tires but it'd be worth it to have everything new.

Borgeson is off the radar at twice the price of a FR.