Bump because I have a 2015 and suspect a boost leak too!
2015 Fiat 500 Abarth
Power: Tork TB, V3 intake w/K&N, HPSI ram air boot, GFB DV+
Handling: H&R 5mm spacers, El Gato Front Braces, NeuF Rear Torsion Bar, NeuF Front sway (full soft), Tork Rigid Collars, Camber bolts (-2.0 degrees)
DSP/D-class (local club classing)