I have been researching various options in getting my 2007 Jaguar XK (X150) 4.2 normally aspirated engine to sound like the true 4.2 liter engine as it was designed. I like the factory sound that was developed for the American market but, it bothered me that the sound was engineered/modified through various means that seemed artificial. Yes, I realize one could argue that the existence of a muffler, silencer, catalytic converter or for that matter a tail pipe is an engineered modification. I wanted a slightly deeper tone but, not one that resonated throughout the cabin when traveling at speed (neutral demand).
After a lengthy search of information which included converting the exhaust to the XK-R back box, I decided on Mina Gallery Performance Exhaust developed for the XK. The Mina Gallery performance exhaust provided exactly what I was looking for in the deeper sound at idle and acceleration. Surprisingly and pleasantly, the sound in the cabin at cruising speed (75 mph) on the U.S. Interstate highway (neutral demand) is slightly quieter than the factory exhaust. That may be a function of my wishful thinking, but the difference at that stage is at least unnoticeable. If I accelerate the car, making a demand, and raise the rpms, yes, the deep tone appears, but then quickly settles down to normal cruise sound levels once the increase demand on the engine is gone.
In conclusion, I love the enhancement. It was worth every penny!
This is not an endorsement nor advertisement for Mina Gallery, just a humble XK owners opinion after an extensive search in trying to make the car sound more bold.