If you're pulling the headgasket might as well do the whole rebuild in my opinion.  When you changed the Timing belt did you change the water pump?  DO IT if you didn't.  The head is super light and took me about 45 mins to pull off my first time. 

I left the intake manifold on the head when I pulled it off it saved time. 

Drop the oil pan and push up the pistons, replace the rings, and replace all your gaskets.

Yes I'd replace everything while you're there.  Ways to boost HP without turbo?  Put higher compression pistons in the bottom end while it's apart.  Take the head in to get ported.  There's a lot to do.  What are you looking as far as cash spent?

$500.00 for a set of 10.5:1 JE pistons

$309.99 for a set of Eagle connecting rods (not needed but worth it if you plan on adding on in the future)

$400.00 to port the 420a head

$89.99 for JE piston rings

That's just a couple of ideas.

how much to port the 6g73?

even if u just repalce the head gasket, u have to get the head decked and should get it pressure checked and make sure the seals and valve/guides are still good, theres cash there, then + timing belt equip, ur lookin at 300+.  but u should havehead ported along with the in manifold, and dont up the comp ratio unless ur going to do sumtmthin..like built nitrous....thats just a wast to up a CR for a few HP...if ur gunna do it, do it right and do it big, i agree, spend the 3k and have a built and boosted.. ull love it.. haha, i love mine!!GL