The top of that piston looks just like the 3 I pulled from my 01 with only 80k on it. You might wanta get that boost gauge hooked up before you romp on it, my failure was caused by a failed cat. "See my posting a year back" The cat failed and restricted the exhaust, took it to a dealer to diag an overboost problem and got it back with new plugs, wires and 3 chunked pistons...
They did give me a new cat back system.
Now where can I find a good down pipe under $200 ??