Okay, I know this is a funny question but I was walking around my 2012 xkr and noticed that alot of the rumbling from the engine seemed to be coming from the middle of the car, not the exhaust. Now the only reason I bring this up is I have had vehicles where exhaust pipes were loose so sound and pressure were coming out from there...so is this normal to hear the growling/rumbling from the middle underneath?

 

Sounds are impossible to diagnose online because your definition of what you hear isn't what the reader will imagine. Cell phone videos sometimes help, but the mics usually don't have the range to pick up on the subtle sounds a trained ear will be listening for. When I first got mine, there were some noises that concerned me but turned out to be normal direct injection noises. Your options are,

1) Put the car in the air and have a look yourself if you know what to look for. If not...

2) Have a shop give it a listen and a look. Or...

3) Bring it to South Ogden, UT and I'll give it a listen in person and help you fix it if there is something wrong.

I know this is of little to no help, but it's going to be the most honest you can hope for. Or, I can say that yeah, sounds like your catalytic converters are going bad or that you have an exhaust leak by your muffler bearings, or some other WAG with absolutely no basis, and send you on a wild goose chase that will waste your time and money.