The Relentless one - like most aftermarket DPs - still has a flex bellows which is way too short. Nobody seems to cotton onto the fact VW used a very long flexi for good reason. Very short flexis can transmit vibration into the cabin, as well as restricting movement (not just for and aft, but also laterally when hard cornering) which can break off turbo flange studs, or fracture the DP > flange welds.
Absolutely buy cheap, buy twice......or in this case, you can buy 4 crappy ebay DPs for the price of one decent one, such as APR or Milltek (cast).