I wish there was a switch I could install on both my diesels, to make them belch a nice cloud of black soot and smoke out the tailpipe on command - I've found that to be an excellent anti-tailgating device. When I have hit on the right conditions and was able to make either diesel belch a respectable cloud of smoke in a tailgater's windshield, it seems to freak most drivers out, and I've had some of them come to almost a dead stop.
It's like they expect black smoke out of a large truck or Cummins/Powerstroke/Duramax pickup - but it surprises the hell out of them when a supposedly "normal" sedan or Jeep Liberty does it.
