The ball-bearing turbo won't spool faster, nor will it give you any more power. It's just a different style of bearing....one that requires separate complex water cooling lines. Normally, only larger turbos have the ball bearings.
Ball bearings in a turbo are likely to be ceramic. As such, they are less forgiving than a sleeve. You have a magnet in your oil pan ? A good idea anyway, but really a good idea with the ball bearings.The siren means something is not right - wheel put back on out of clock with its balanced position, blade rubbing the housing, etc. These would happen with ball bearings too.I'm happy my turbo is floating on a cushion of oil rather than riding on glass.Some guys run their turbo sans airfilter so they _can_ hear the siren ! :-D
The magnet is a good idea for sure.But Ceramic isnt magnetic :shock: