WRX EJ20 Engine rebuild; stock or upgrade

[happy1]

Hi,
I have been collecting two damaged WRX engines from Quokka, and I was planning to rebuild them and use for a dune buggy or re-powering something else They are both MY01 or newer, EJ20 with variable cam timing system. I expect both of them to need crankshaft re-grinding and new rod for sylinder #3, since this seem to be happening to most EJ20s. I haven't opened them yet, but that would be the normal damage, to find a spun bearing.

What parts should I upgrade while at it? For example new stronger rods?
Also who sells the cheapest rebuild parts (bearings, gaskets etc.)

Thanks for your reply.