Only problem I see running it inside the cabin is if the meth line ruptured meth will spill into the wiring harnass under the carpet and also the fumes are not too healthy to inhale. Also a ruptured line there will be no way of knowing for awhile as the carpet would soak it up. Either way best to have it under the body panels.
*CODING BMWs in N.Y Area 917-939-4980*
Call or Text for more INFO