Welcome and congrats on the good find! Post some pictures of your foot fortune when you get a chance. The seat is easy to fix, the alarms are a bit testy on these cars and since they were evolving quickly there are several different renditions making it difficult to find helpful postings. I'm sorry but I don't know the details about whether the bumper for a 540 is different than a 525. I know it can be, but I'd also imagine that the 525 bumper will fit if you want it to.
What year is it? If a 95, I think they had upgraded bumpers and that may be worth looking at.