For simracing - a set of pedals with a load cell brake. Building muscle memory for the force you push on the brake is so much better than trying to be consistent with the angle of your ankle. The consistency you can achieve with braking is unreal.
Home espresso - a set of accurate scales and a timer. Reducing variables when trying to dial in a new bag of beans or when chasing that perfect cup is so handy. Like the the load cell brakes for sim racing, it allows you to be consistent and just change small things at a time and then stick to what works.
You know, as someone who likes coffee, I've felt the gains at that level of precision to be very marginal. I've been at places where they calibrate the shit out of everything and I wouldn't say they're better than places that don't, or some of the stuff I've had at home.
You seem like a very cool person, same exact hobbies for me!
For sim racing everyone in my groups are losing there minds over MOZA hardware. I had the chance to try an R9 and instantly fell in love
For Espresso all my friends are still obsess with the Niche Zero and the Decent Espresso DE1. I roast on a Ailio Bullet and am still very obsessed with it!