For a stock engine the biggest pro is the sound the quad throttles make , pure induction noise is sex. For a modified engine it'll get more air in as the quads can flow better. Blacktop throttles are usually big enough for most applications and are easy to get + the velocity stacks are also readily available.
The 20v TPS spins in the opposite direction to the 16v so you will need to swap the wiring around for the signal so it gives the correct reading.
Adapter plates are also readily available for the blacktop throttles, and you'll need a form of vacume canister. It's a fair amount of effort to get the quads on there and you'll need to retune the ECU as well.