My mom has a 2007 Mercedes S550 and today when I was driving it the tire pressure monitor light came on and then "BREAK WEAR" popped up on the speedometer display. The car has almost 70,000 miles on it but thats all highway driving so it shouldn't need a brake job yet! The car was just in for a major service at the cost of $1200! Should I take it to Mercedes, or just get a cheap Walmart brake job?