WRT balancing...you are starting with a completely different set of pistons that weigh more than the stockers. Whether or not you replace the rods as well, either way I would recommend a balance of the recip assembly. You might get away without doing it, but why go through all the BS of assembling a complete motor then find out it has vibration issues down the road? Do it now and you'll soon forget about the couple hundred the balancing job cost you.
