a couple of mates of mine have put there ae71's thru vic roads with 4age's in them and vicroads not notice. because with the 4ac, the eng no# is 4a***** and then 4age is 4a***** so yeah, not sure about 4k tho. other thing is you could get it engineered. wouldnt be that much.
as for rear window, chrome strip comes off, when you pull the front windscreen out you need some special tool, i take it, it would be the same for the rear.
good to see that yor getting into to it! sing out if you need a hand.
edit: ahh i got confused with thread lol.
you can hit the underside with k&h sound deadener. thats works well. used it on my old rat rod and it was great!
Yeah i saw your ute i was like "hey that looks really clean,hang on... that looks familuar.. Dude of ae86!!" lol.