Originally Posted by N8GTOL

Tony just installed my F.I. w/ 18" res. last weekend (still have stock cats). I too was wondering this for a long time before purchasing.

Fit, finish and craftsmanship are second to none. Although not fully broken in, my first impression is that it sounds great but I was a bit surprised at just how deep and loud the "quietest setup they offer" actually is in person. Tony and others tell me that this system settles down a bit (~15%) after a few hundred miles which is typical of most performance exhausts. This is by no means a negative comment, just unexpected. Between 1.5k and 2.5k rpms the system seems to be at it's deepest and loudest in the cab. There is a slight hint of what some may call a "drone" as you pass through 2k rpms, but it comes and goes quickly and is completely tolerable for me. As you approach 3k rpms it turns turns into a symphony of automotive performance and I find myself revving higher than before. No rasp. The tone is deep and smooth.