Go for it. Your engine is fine. I know a couple of guys who are tuning original unopened blocks on Buick Grand Nationals and T-Types. Upgrading from stock turbo. Some are at 110k miles. They are just fine, because they are taken care of their cars.Thinking about a basic tune but ... 85K on the clock. 95+% highway miles, always driven for fuel economy, full synthetic oil always changed with 20% remaining on oil life monitor. Miles not an issue or should I just forget about it?