The N63 "hot-V" design places the turbochargers between the cylinder banks (inside the V). This creates extreme heat that degrades valve stem seals and piston rings prematurely. Oil consumption of 1 qt per 750-1,000 miles is common.
Symptoms
Oil level dropping 1+ quart every 1,000 miles, blue smoke on startup, oil fouled spark plugs
Fix / Remedy
Valve stem seal replacement for moderate cases. Full top-end rebuild with updated seals and rings for severe cases. BMW issued a "Customer Care Package" for early N63 models.