[DarkPira7e]

Reducing power is not going to help with reliability at all. Putting all hardware back to stock can help though- heat management under the hood is one of the biggest long term contributions to a long life for things like your coil packs, wiring, plastics, etc. stock headers have heat shielding and most aftermarket headers don't.

I'd freshen up some bushings, engine mounts, put the stock headers and stock tune back on. It'll have a great life