im in a similar position, my 2.5NA stsrted to make a ticking noise so i checked the hot spots the were cracked so i replaced them, only to find the tick came back again.

so after reading bits on here i had the head off to check the cam followers and 1 is damaged. but i think im going to drop the sump pull the pistons and change the rings as well while im in this deep. you are right the head id a heavy lift, just eat 3 shreaded wheat before hand it will be ok lol