^agreed it depends on wether u wanna go all motor or boost....i would have to say go with a b18c1 if u wanted to go boost because its basically cheaper to purchase initally and ur gonna wind up changin a lot of parts in it. and really if u wanted to go boost, id think about stickin with the b18b1 block and doing a ls-vtec setup with a built lower end.
if you want all motor well the b18c5 would be better cuz ur already gettin a higher compression ration...