best engine swap??

I recently aquired a 1990 honda civic DX with the 1.5L and a 5 speed manual. somethings wrong with the transmission, if its not the linkage, im goin to pull the engine. i want to put a pretty nasty engine in this thing, seeing as the car was given to me for free, i can waste some money on it. what would be the best engine/tranny swap that i could do without some extensive modifications? i already have eveything from the front seats back stripped down to the metal, the carpet is gone, and the battery has been relocated to the trunk. any help would be appreciated, thanks,

matt

GSR, LS/VTEC, B16A.....they'll all work for you and i'm sure Hasport has mounts!