is there any signs that can tell you if they are going to blow open
You'll probably see a cracked or broken weld, or excess rust around that area. Better off just getting it welded up before it happens, becuase after it blows, it might not be repairable.
I'm guessing TPR has this problem fixed?
TPR won't have this problem, and no exhausts besides HKS or TRD
have it, either. It's just a crappy muffler design from HKS that's prone to failing. TPR's mufflers aren't from HKS, so there will be no problems with it.