The reason why oil gets past the turbo seals is because it doesn't have any!!
You can get the step gap modded, the seal as such is simply a ring like a tiny piston ring, complete with a gap between the ends to let oil through, but a step gap seal sorts 90% of this.
Bronze is ok, better than std, but COLSHIBO is expensive for a reason, all my oil's going past the shagged rings!!
tabetha