Quick reply
The turbo block is semi closed. The pistons and rod and crank, injectors, coils, ecu, cams, wiring, gearbox, diff, propshaft, front brakes, brake booster, intake, radiator, powersteering rack, clutch, head casting number, tgv housings, timing belt due to head, crank pulley, oil sump, g/b shifter, engine harness, is different.
Inside the gearbox, the lay shafts are thicker, the gear width is wider, The clutch disk is thicker and wider, pressure plate has more fingers and higher pressure. The diff is LSD. Either vlsd or mech lsd.
The clutch is hydraulic , self adjusting on the turbo. The NA has a cable clutch.
The turbo model has better hubs, to deal with the extra heat from the brakes.
The ABS unit has a different programming on the NA model vs the turbo.
Of-course the turbo model has, turbo, inter-cooler, oil water heat inter-changer and different type of oil and water pumps. But the addition of these items results in different routing of oil and water pipes and more oil and water pipes to service these additional parts. For example the turbo is water cooled, to ensure the turbo does not coke the oil in the turbo bearings, there is a coolant header tank on the turbo engine that does not exist on the NA model.
The addition of a turbo requires more volume of oil and more pressure. So a different oil pump is used.
The turbo model requires more fuel, so the fuel pump is bigger and has a higher pressure. The lines are therefore thicker.
On SOME turbo models the powersteering, has a cooler. On some turbo models the clutch has a fluid cooling loop.
The exhaust headers are different and made from better material. Due in part to the added heat, they will experience.
And so on...