Yea, if you're on the stock axles and you go to 38s, you're way stressing what these axles can handle. Not very many people run even 35's on the stock axles, some do, and get away with it, but bigger than 35's and you're most definitely asking for disaster.
Yes, D60 are definitely the best way to go, at least for the front. in the rear you have some other options like D70 or 14bolt. But definitely D60 for the front.
If you're not looking to spend that much money, at the very least, look at upgrading your rear axle. The ford 8.8 rear swap is pretty brianless. And you can strengthen the front with Warn alloy shafts (1 piece, get rid of the vaccumm disconnect) and run the new 5-760x ujoints. throw in the Warn manual locking hubs that upgrade you to the 5 on 5.5 pattern and you've added some strength to that D30... Though not enough to run 38s IMO. But the rear D35 has got to go!
Or another option would be look at getting a pair of Full Size Jeep axles, Cherokee/Wagoneer/Jtruck. Some years came with D44's both front and rear. those would make a good swap. And would upgrade you to 6 lug wheels
1995.5 Isuzu Rodeo - SAS'd and SOA'd, sitting on 36x12.50 TSLs, D44 front, 14bff rear, locked by OX and Detriot, suspensions by Jeep and Chevy, high steer conversion, 5.13 gearing and Teralow in the case.