V6 smog check

i don't have emissions but try the sock test... put a white sock on your tail pipe and rev it tor 10seconds and if the sock looks some what clean and isn't covered in black stuff you should be good.
and go to the parts store and they should have something by the fuel additives that says it will help you pass emissions. it's a small red plastic bottle

should be fine with modified intake and exhaust, as long as you still have a good cat

my 92 3vz barely passed emissions last time, 1/4 tank of premium ethanol fuel and 4L of methyl hydrate in the tank