"Anyway, version 2.0 of my car, shown below, has an under car exhaust system built by Dr. Gas. "
Jim, do you have any under car photos of how the system was put together? Would be interesting to see how it was done.
For the dual system, this past year or so, there was an electrical gate system out for cutoffs though only for single pipe systems, not four dump tubes. Seems it will only be a matter of time until some innovative rodder comes up with a way to use an electrically operated gate system to shuttle between side pipes and under the car...now that would sure be the best of both worlds and save having "dummies" hanging on the side. Over here, we see a lot of cars with an extra pipe hanging out the back to look like dual exhuasts, some of them only use a tip rigged on the bottom of the bumper, pretty tacky.
Ken