All that advice and then some more...I AM SO GLAD that I had a under powered 1972 beetle. Before doing mods to the car, have good measurement/instrumentation. OK, are you getting 32 MPG
highway? Less/More? Performance is just more than going fast (we all like to go fast) being efficient is part of the equation. So go buy a scan gauge. Doax has the info on those and maybe have some for sale.
This should be your first mod to the car: ScanGaugeII : Linear Logic - Home of the ScanGauge
OK let me repeat that, this should be your first mod! Maybe a better radio after that....Leave the car stock for now and learning how to drive to get the best MPG is challenging.