Exhaust leaks definitely causes more engine noise as the ecu compensates with more fuel. I had a broken bolt on the exhaust manifold down to the cats. While removing the heads I found both heads with broken exhaust manifold bolts. I ended up removing the heads to remove/replace the bolts, complete engine gaskets, the bad exhaust manifold with stuck broken bolt and broken extractor, redo timing (done less than 1 year) with zero slack, retapped every single thread on the head and block, new head bolts based on engine block serial stamp, torqued to workshop manual spec, and redid all cooling parts.
I removed both heads to do both exhaust manifold gaskets and knew what I was in for. It took me 3 days straight with probably 8 hours of sleep to get it all done before my big weekend off road trip. Luckily I had 3 hours to break it in before heading out, but still... it's a BIG job and you can definitely squeeze everything that needs to be done into that job.