Hi mike Firstly im Jealous, I love the integrales, they are pretty rare. I hope you are looking after it.
They sound similar to the turbos used by VAG group (from my research the K03 was I beleive a KKK unit). Are you doing any other mods? (Wastegate,mapping, BOV etc?)
You have the option of a rebuilt KKK casing with k04 Internals or a highbrid. Anything will ball bearings will be far superior to the standard thrust bearings and spool up more quickly.
Do you have a power figure you are aiming for?