IMHO thats an old way of thinking your 208 should be fine and provides a way better low range than a 205 or 203, its main disadvantage is the slipyoke.
Np203 full time cast iron case huge weighs alot basically a 2 to 1 low range chain drive
np 205 super strong cast iron case lighter than a 203 but still somewhat heavy 2 to 1 low range gear drive
NP208 Aluminum case 2.6 low range lighter than a 205, chain drive and a slip yoke on the tail shaft
NP241 Aluminum chain drive case I think low range is 2.72 and you can put a slip yoke elimintor on it. IMHO the best t-case of the stock ones for an all around rig thats only midly built.