After 3 months of work, my car is back on the road after a diy transmission rebuild. Through this process (I did the project on jackstands), I removed most of the underbody panels for easy access and misplaced a few of them. A friend of mine owns a sheet metal shop, could I replace these panels with polished sheet metal? I don't want to pay the bmw tax for these plastic panels but I am worried about underbody temps.