you can supercharge the A15 pretty easliy.
you should get an engine importer to get the supercharger and intercooler off of a jap spec toyota supra. the 4AGZE is a ok super cahrger but because its a positive displacement supercharger you wont get a good noise from the blow off valve.
the supra charger can be fitted easily to a sidedraft weber carb. and the intercooler can be mounted behind the grill with little of no mods i think. you should do a port job on the head and get a 1mm head gasket. other than those and the weber no more mods are needed, andit will smoke the bags easy as.