I have not. It feels very song and volume dependent. The sub is back there and will move some air, but it doesn't consistently hit like I prefer, especially not at low or moderate volumes. I'm not someone who has ever had any serious aftermarket subs or unrealistic expectations about car audio. An 8" powered sub in my acoustically horrible Jeep Wrangler Unlimited with a soft top delivers more than enough. The sub in the B&O system in my old Audi S3 was also perfectly sufficient for me. I love my Y, but the subwoofer is pretty mediocre compared to just about everything else about the vehicle. I'm just not sure I want to do any upgrades that are not plug and play.