Hey i bought a '91 civic hatch last friday and needless to say the power is pretty pathetic... its got the D15B1 in it with a 4 speed tranny

... I know my fair share of info on honda engines but not everything so thats why ive come here... I would like to swap a B18 or B20 but im still in high school and cant really afford to (and if i did my g/f would kill me and shes #1 right now so i cant tell her to get lost) so i came up with the idea of swapping the head from a VTEC D16 if it was possible and i wasnt sure if it was... i think ive heard that its called the "mini me" swap or something like that... is it possible? if so, approx. how much of a gain will is see? will it be through the powerband or just the top end? i also want to get rid of the 4 speed (:bbb: ) and get the 5 speed that was offered... would i see a noticable change in that too? how much power would the bottom end be able to take before calling it quits? are there any "free mods" like with DSM's that would give me some power for little or no cost? what is that round thing on top of my intake manifold?is it a MAS or something? do i need it? sorry about all the questions guys but im dont know a lot about this engine and im in desparate need of help and i know youre all very knowledgable in this area... thanks for all of your help
-Josh