Getting that extra growl from mk1 ???

So I guess this question has been asked a hundred times already. Cone or De-trumpet ? Most tell me the cone would sound better but performance would degrade due to the hot air from the engine bay to the cone. Others tell me to de-trumpet the airbox. Sound s great yea but how on earth do you actually do that??? I got a 1990 MK1 Citigolf 1800 Sport which is still carb. Any advice or help guys ?