To solve this expression, we need to follow the order of operations, which is parentheses, exponents, multiplication/division (from left to right), and addition/subtraction (from left to right).

First, let's simplify the expression inside the first parentheses:
8 - 159 = -151

Now, let's simplify the expression inside the second parentheses:
8 - 73 = -65

Now, let's substitute these values back into the original expression:
(-151) - 159 = -310
159 - (-65) = 224

Finally, let's subtract the two results:
-310 - 224 = -534

Therefore, the answer is -534.