Looking For Suggestions on my 95 civic hatch dx
 

I am planning an ecomod on my Civic and had the following questions.

What engine would be best for fuel economy? (wouldnt an obdII conversion be worth its weight in mpg?)

? d15b, b18b, d16z, d15z ? & obd 1,2,3

Does anyone know of a good place to get the motor from?

Thanks
Moonie