Ran mine every day close to 2 years & the only issue I ever had was some random jackass kid dumping a red solo cup full of fruit punch & vodka down it last summer. Started it up for work the next morning & a red solo cup flew out & puked sticky soot all over my hood & fender. Other than that I drove everywhere without a care in the world. Drove right by city/county/state/dot officers daily, half would look & the other half never paid attention. After fighting the 3" DP in & how tight my engine/firewall clearances are I wish I left the damn hoodstack on. On the other hand with a 3" down pipe dumping out behind the tranny cross member the EGTs really didn't change, that's cruising/mild/WOT.
I don't recommend them to anyone for a street truck. I had no issues with mine but I just wanted a more normal looking farm/work truck. As far as the whole "exhaust inside the cab" thing, only time I had that issue was if I left the rear slider open & it rolled back in. Or when the tuning was off & it was fueling like a 3.0 pulling truck & the wind was blowing on across the side. I don't have A/C so both windows are down all the time. Noise really isn't as bad as you would think, anyone that rode or drove mine will back that statement up. I've been been there & done that, I'm over it.
Show you the flight path of the exhaust on a cold drive to work-
It found a new home on another truck, swapped him hoods so now I just need to swap with someone to get it color matched or do a 2" cowl.
Other guy's truck with my old setup-