water comming from your tail pipe is going to either be just condensation or coolant, i'm sure u'd know if it was coolant tho coz it would be a big white nasty smoke.. either way.. that doesn't mean that your cat is bad.

if you have 4k

i'd buy a b18b swap & boost it via turbo..

your not gonna be able to afford a b18c & super charger with 4k.. sry man :sad: