I have a 2000 M5 with 114,000 miles. Yesterday I let my fiancée drive it while I chased her in my raced-prepared 911 turbo. Each time that she accelerated, I noticed a puff of smoke emit from each tail pipe. The M5 currently drinks a quart of oil every 1,500 miles. Any suggestions on diagnosing or correcting the smoke? Is this normal for a high mileage car?