I would screw the new .308 barrel on and put the money saved into more ammo. What can you do with a .358 that you can't do with a .308? Are there grizzly bears or something where you live? Plenty more .358 stuff on the shelves than there is .308 stuff? Perhaps one likes the bit more added recoil of the .358?

All in jest (mostly). Do whichever makes you happier.

"You can lead a man to logic, but you cannot make him think." Joe Harz
"Always certain, often right." Keith McCafferty