I have bought new stretch bolts and have reused. Usually the dealer keeps them in stock and somewhat reasonable. I believe the flywheel bolts are 12.9. So wayyyyy better than the grade 5 (8.8) I've seen on domestic flywheels/flexplates.
If your flywheel looks as glazed as your pressure plate in the first page. A break in will be really needed. Big ole slippery burnout is the preferred method to this task.
