$800
There is one before and one after the catalytic converter.
The fuel lines around the filter; you will need an adapter.
about 300.00 start to finish if you do it yourself
$40 - $50.
Both the 1.6L and 1.8L engines in the 93 Prizm are 4-cylinder inline engines. I'm no expert but I don't think you can get a V6 engine in the engine compartment let alone hook up the transmission, etc.
If you are paying someone to do it: a 1994 Thunderbird SC V6 3.8L will cost about $1,800 if you live in Southern California. If you are doing it yourself: parts will be about $800.
It depends on the year and engine an average 3.0L V6 DOHC 149.99 @ O'Reilly Auto (premium set) The pistons are 40 a piece.
I believe the 4.0 liter SOHC V6 engine is ( 210 horsepower )
260
160hp
It is listed as 210hp