fuel injector question cont'

ok i posted this thread a week or so ago (http://www.automotiveforums.com/vbulletin/showthread.php?t=377939) and i changed the main relay, and tonight, car did it again, the code 16 has gone away (check engin lights off anyways) and it still wont alwse start and sometimes when it does, it will purrr nicely, and all of a sudden bog down for a quick second then pur, then bog, its like its happening every 2 or 4 cylenders apart, so im back to the original, i can smell gas, the main relay seams to have fixed the problem of fuel pump not priming, hopefully tuesday i will check for spark, i should have that, electrical is all fairly new, but if i have it and i do need to change the injector(s) (89 dx, d15b2) should i just do a swap and go or mpfi? i know i get more power from mpfi, but how much $$ is it going to run me once i have it, ill get the part cheep, but what would fit, what do i need, and how much wireing and computer work is there?? thanks again guys

btw, the car will sometimes start, sometimes start verry hard, and others, well i wind up pushen it with my truck around my shool parking lot with a buddy to get er goin, any ideas what it could be if its not the injectors?

may be vacum leak or coil
mpfi swap---4 injectors
----resistor
----4-4ft wires
-----intake mani
www.4thgenerationcivic.com performance swaps

well after a push start im moven away from the injector to possibly a bad starter, worn our brushes or something

so how much is a brand new starter running now a days for these things? and how hard is it to take them out? as with most things, if i have to i can pull things apart and 9 of 10 times they come back together with all the parts put back how they came off, just need to know if i should plan a full day on this or not