There is a low gear swap possible for the NP203 range box making it possible to put 3.1:1 low gears in it. If you run a doubler (Np203-Np205) then this makes the choices 1:1, 1.98:1, 3.1:1, and 6.045:1. (Without the lower gear set it comes out to 1:1, 1.98:1, 2:1, and 3.96:1) As I recall it costs about $1000 for the gear swap and the NP203 case has to be sent in to be reworked. Add the $500 or so for the adapter and a couple hundred for incidentals and it's possible to get those ranges down to 6:1 for under $2000. $700 or so for 4:1 or close to it anyway if you use the stock gears in them (That's what I run BTW). This doesn't include drivelines though which will need to be reworked most likely. I still run a stock rear driveline but it's used for my frontend instead of the rearend. Originally I used the front driveline in the rear but that was a few drivelines back. It took me 3 of them to get one that would hold up. In their defense though I built the rear drivelines myself so it was a gamble on them right from the start.