I just finished with the gronk kit last weekend, and dropped most of my exhaust pipe around the same time. I've been driving to and from work with nothing but the intermediate pipe that comes back from the downpipe off of the manifold... and I haven't noticed much of a difference in cab air quality, I must say.
The "exhaust leaks" are a bit louder than before, but not a lot.
I don't think much was even
getting to the muffler before anyways!
I'm hoping to have time to address that this weekend.
Still dreaming about a wideband O2 sensor and afr gauge... that's going to be fairly soon, I feel the clock in my cluster needs to go.
I've decided to fork out for the digital aem one