I put on my S3 the IHI VF34 ball bearing turbo with custom downpipe, 550 injectors and tial external wastegate.
I wanted to tell you guys because you can not find info about big turbo upgrades so easy on this forum. the power on the dynapack dyno is 365 bhp with 1.5 steady boost until 7500 rpm. The car goes great , better than stock (like drivebility,not power) and the lag is the same as k04 if not lower! this ball bearing is incredible.