The S-AFC probably costs about $770-700 (shop around)and is a generic (one model fits all) device that alters the MAP signal vs RPM to fool the ECU into leaning/enrichening the mixture. They can delay the boost cut by fooling the ECU that the boost pressure is under the boost cut limit.
It does not remove boost cut or speed limiting. The RSM (rev speed meter) can be hooked up to cut out the 180km/h limit