the pistons are different part numbers, since they are different.
the crankshaft has a different bolt pattern since the automatic flex plate and maunal flywheel have different bolt patters (dont know why)
the rods probably have bigger rod bolts, but are the same otherwise


compression doesnt matter when it comes to operating temps, the combustion chamber runs at the same temperature.
Theres space for the turbo itself up out of the way, as well as the exhaust piping. Most people just get lazy when it comes to charge piping and they run it straight under the car.