hey, just fitted full stainless dansk system and modded airbox(carrera cup style) but when im driving can hear a hissing sound like darth vader is riding on rear wing, has anyone else experienced this or am i hearing things. also just got a set of fuchs 7x16" front and 9x16" rears whats the best size tyres and any prefered makes (want to lower the car about 30mill) hope everbody is enjoying their cars thanks