Yea the powerflex dog bone bushes give more vibration through the cabin it's normal. If you uprate the upper engine and gearbox mounts with vibratechnics or VF engineering then you'll notice alot more vibration, THS mounts aren't so bad but they also increase vibration through the cabin. If you've only just fitted the powerflex dog bone bushes it will get better as it beds in but there will always be more vibration into the cabin than OEM bushes and your steering wheel will still vibrate on idle after it's bedded in. If you don't like it you could always swap out the bushes for stiffer oem bushes like from an r32, lcr, s3 etc.