Going to map my car with ecutek end of the month for the first time.
Having never had a turbo car before this or ever mapped/chipped my cars I'm not very clued up on this topic so excuse my stupidity if you will

Once the car is mapped does tinkering with the engine affect it?
For example if I took it to Subaru for a service and had parts replaced, or if they repaired it and had to replace engine parts will I need to get it mapped again?

I ask this because people say that with every new mod ie. exhaust, decat, etc you need to tweak it.

 

With a decat exhaust/CAI you're changing the breathing characteristic of the engine in a major way... so a re-map is recommended because:

a: to make things safer ie correct fuelling and boost control,

and

b: to release any power/torque as a result of the additional air/fuel being mde available to the engine.

Just by replacing oem parts with other oem parts the map will not need to be modified no..the subaru ecu is quite capable of adjusting to compensate those smaller changes.