The HG swap itself isnt a big deal. The pain in the ass for your averag DSMers is that you are basically doing a timing belt job at the same time. If it hasnt been replaced yet, do the full tbelt job. If it was just done you can reuse the parts, but still have to time it and tension it. You can do the "RRE method" (search thier site for instructions) which requires a tensioner tool either bought or made, but doesnt require you to retime or retension, if you do it right. This method however doesnt apply to 2g cars with a 6 bolt motor.
Also bear in mind that HGs dont blow for nothing, odds are you were knocking or something else went wrong. And I would definitely do ARPs while you are in there. Search
www.racingknowledge.org for a thread I started titled "ARP head stud info" or similar, in the DSM section. A couple important pointers for doing the head studs properly.