No, this should not void your warranty but ideally you would want to check your local laws. Here in the US the tamper stickers were recently made illegal. If you still have tamper stickers in your country you should verify the legality before breaking them.
However you should return the machine to stock before submitting it for warranty service. Two reasons: in case they need to replace your machine you would lose your upgraded parts. Also so that any issues cannot be blamed on your upgrades. If you have modified the machine they might just say it is your part causing the issue.
Of course do not damage the machine when working on it. If you damage anything your warranty may be denied.
A bus station is where a bus stops. A train station is where a train stops. On my desk, I have a work station…