Tune for 2015 e400?

I have a 2015 e400 4matic w212 with 125k miles.

I gave it a full suspension refresh, installed high flow intake, staggered wheels with performance tires, and im about to install 4 piston brembos.

This car has the twin turbo m276 engine. It makes 330hp 350ftlb torque.

Other variants with this engine like the c43, e43, and 450 models push closer to 400hp.

It would be nice if I could make this car closer to 400hp but I dont want the car to destroy itself. Ideally I would like to get over 200k miles out of it.

Has anyone done a stage 1 tune on an e400 while sustaining reliability? What is my best option for a tune?

I was thinking about piggyback modules like the racechip but those have some mixed reviews about their power gains. I dont want to take it to a shop and want to tune it myself without a dyno. What's my best option here?

Should I do the tune at all or leave it stock? I feel like this car could handle a lot more power but I mostly drive it in eco mode anyway. It is my daily driver.