I am look to swap my 4g94 for something. I'm not too sure what will fit in it without doing some major work. I heard a 4g64 would work.
4g69 from a 04-06 RA will fit....but the downfall is the part selection for the 69. I know of only 3 manufacturers that make headers...and the cheapest is 350 or so.
I've seen the 4g64 swapped in a few times, the 44g63 a few times, and the4g 69 like once. Just need to time/money to do it.