Head gasket is a once every 150k ordeal. Not hard to do either. It was one of the very first things I did on my car when I bought it all those years ago.

As long as the engine runs smooth, with no hesitation it should be fine.

Check for mixing in the coolant, and in the oil fill.
Check how long it takes to engage in reverse. More than a couple seconds means the trans is tired. Mine has been getting progressively worse for the last 3 years so bear in mind that it's not imminent failure

__________________
Eugene

10 E63 AMG
93 300te 4matic
07 BMW X3
14 Ford F-150 Fx2