My first question would be why ? What are you expecting to gain from the straight pipes ? More HP, cooler sounding exhaust , what ? I really don't have a lot of knowledge on this particular vehicle . Does it have a carburetor or is it fuel injected ? Does your local area have emission testing ? If so , it would be a definite no - no ! The manifold could be replaced with the three pipes if you have a suitable exhaust flange to weld the pipes onto . Since this is a FWD / transverse mounted engine ( I'm assuming ? ) , then space in the engine compartment is at a premium and I'm not sure there would be enough space for three separate pipes to snake through there and then all the way to the back ? Anything is possible if you are determined to do so . What year is the Geo Metro ? Sounds like the $ 2000 price tag might be a little steep unless it is in mint condition ? If so , you would be killing the value of the car to go through with your plan ! Just my
, take it for what it's worth ! Good luck with the direction you choose to take .