Info on the MPFI swap: (from the FAQs thread at the top of the forum)
http://www.angelfire.com/d20/hcivic88/dx-siwiring.html
http://www.geocities.com/teampimports/fuelinj.html
http://www.geocities.com/c_rexboy/mpfi.html
http://www.fourthgenhatch.com/mpfi.html
All, look like great info on them...
As for head swaps, theres another thread about this, I suggested the MPFI swap, over the head swap, because the heads are so similar, it wouldnt be worth it to just swap those... But if u swap both, im sure it would be a good solution as well... Then maybe an Si tranny, as they are geared for speed rather than economy...