is it bad...
It won't hurt, but you will have a warmer inter cooler (Heat soak) issue if anything.. I wouldn't loose sleep over it though.. I may be parting with my SPT heat shield since my APS TBE exhaust came with one already bolted on.. If you want send me a PM..
I have a divorced catted downpipe wrapped and I modded the heat shield to put it back on. I would assume your mod of the heat shield would be similar to mine. I just eyeballed it and took the jigsaw to it. Worked ok for me.



