Build it how you want it the first time round. If you don't put steel rods in it then want more power then you'll only kick yourself. If the lateral movement worries you ask a machine shop to measure the pistons and the bores for wear and ovality and you will know if you need pistons. If it was me I'd sell your engine and get the block that has already been worked. 600 is stills cheap rebuild. Mine cost 3k without any ancillaries.