I would say go with an SYE. Your going to have to get custom shafts made anyways, so why get ones made for a slip yoke? Do it right the first time if your swapping in the 231 go with the sye first and get the shafts made to match.

99 Gen 2.5, fixing blown head gasket
89 SWB- 33's, ARB Front locker, SR rear locker/axle, SR F brakes, winch, WST Offroad Armor all Around, 2.85 Aussie T-case Gears (SOLD)
Sold: (2) 95 SR's, 86 SWB, 90LWB, 91 LWB
-Can Change a timing belt in my sleep..