We bought my wife a SBM GT in 2011 with 4100 miles on it. It already had a Frankenstein straight pipe exhaust on it: factory manifolds and cats, mid-muffler removed and resonators relocated, smaller pipe used as filler, no x-pipe, no mufflers, straight pipe axlebacks. It sounded good outside the car, very low and loud tone, but HORRIBLE drone between 1800 and 2100 rpm. Recently had DOD delete done by CHenry Motorsports and the drone range greatly expanded. Today we installed the Solo Mach Balanced catback system, about 3 hours work, including a couple of breaks. After a shake down run everything seems to be as advertised. No drone, somewhat quiet inside the car. Nice tone outside and racecar sound over 3000 rpm. We couldn't be happier.