I am having some clearance issues with my GT Spec frame brace, so I took the heat shield off of the stock Y pipe for extra clearance.
Question: What is the down-side to just leaving the heat shielding off? (I don't think any of the aftermarket exhausts come with heat shielding).
Or should I just modify the heat shields for clearance and re-install them?

 

I'd say your fine.. those exhaust headshields will cause you nothign but headaches in the long run where they'll start to vibrate and make your car sound like crap.