Found mine has a small rust hole, got a mint one from Alter Ego, cleaned it up then got it dipped in rust paint... so question is has anyone replaced one and do you need to do your alignment after, looks straight forward to a degree but is there anything one needs to worry about?

What "subframe" are you referring to?  Second gens don't have a sub frame - if you're referring to the front suspension cross member - there was a recall involving that - there was a "bad batch" of those, shipped out with inadequate anti-corrosion protection, which caused them to rust out.  As far as I know, it's a straight forward remove & replace and then alignment.

Yes the sub frame up front where the wish bones hook up to, I looked up the recall but that ended already  Looks pretty simple so tackling that in the next few weeks once I find some time