you have just enough knowledge and gumption to be dangerous.
Fill in the rest of your knowledge, and you’ll be a darn good DIY’er.
In the meantime- stop going to multiple mechanics (and like was said- Stay away form Sear Auto Center.) Find one you like, one you can trust, and stick with them. That will save you tons of headache, and tons of money. With a Jag and a Porsche, an exotic car mechanic would be a good idea.
There is zero need to have multiple shop look at your brakes.
But messing with your brakes and you SRS system without proper training or extensive knowledge of what you are doing is a very risky move. When you have a pro check your brakes, show them your SRS system repair too.