07 Access cab exhaust

So I've started to hear some serious "rattling" or tinging sound coming from my exhaust and I can't quite put my finger on what the hell the noise is. I have a feeling it's coming from inside my cat and if that's the case I'm probably going to need a new exhaust. I have a 2.7 and I know I know, putting straight pipes on a 2.7 sounds kinda silly, but has anyone actually done this and have some valid sound clips of what a 2.7 NON TRD sounds like with straight pipes? Sure seems like a way easier and more wallet friendly then slapping a whole new aftermarket exhaust on there. Any info would be good. Thanks!

 

Anyone?