I have a second hand Xbox 360, outside warranty

I have a second hand Xbox 360, outside warranty with three red lights, secondary code 0102, I took the outer casing off to see if there was any physical issue and noticed the warranty sticker was not in the correct place. I have seen several guides to fixing the issue with the GPU myself but am unsure how strongly this would be recommended for and against (the repairs I am looking at are heat and connection pressure issues not overheating) Any advice appreciated