I would do this if you want a Large Lift like you said 6"-8" then you need to do a custom lift thats is if you dont want to piece 2 lifts together. I would say go with the SAS and go one of 2 ways. Coils or leafs. It is cheaper to do leafs because all the thing you will need can be easly found at any junk yard Just find a full size chevy or ford. Then all blocks and shackles. Hell you can go even bigger then what you wanted to in the first place at this point its skys the limit. As for keepin the same rear axle If you are goin of a d44 up front you should just put at least the same in the rear matchin then up in the best bet so the stress is equaled out. and you dont have to worry about the stock ford axles givin out.

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2001 Ford Ranger Edge Plus 3.0L 4X2
Installed rear 2" block's, Cranked T-bars, 3" body lift, Goodyear Duratrac 33X12.5X15, Aluminiam Ion 15X10 Rims, Crane 1.72 roller rockers, K&N intake, 3" Cat Back Custome Exhaust, 8.8 rear end, 4.10 gears, detroit locker.

In process danna 35, M5R1 4x4 tranns, NP205 devorced T-Case, front 4X4 spindles, SkyJacker coil over shocks front and rear.