Before you start throwing money around make sure your float levels are
There are no differences between the 1600 and 2000 other than drivetrain and
if the 2000 motor ran well in a 2000 it will run well in a rebadged 1600.
The gas lines are the same also as is the pump for the most part.
You don't need to baffle the tank as there is a baffle in there already.
Taking a roadster to an un-informed mechanic is dangerous to your wallet.
Like I said check your float level. The fuel should be just a tad lower than
the carb body/nozzle. You can bend the tab on the float to get it to the
correct spec. Takes some time but it's very important to get the car to run