The tr6 won't work directly due to the different ignition inputs the old 3.8 use vs the 3800. If you could sweet talk Bob Bailey into modifying it for use with 3800 that would be sweet.

That is the two step I'm using, with opto-isolator on input signal. Haven't tried the ignition retard or anything, as I'm not sure now that the signals are compatible. However the two step works great now. Just have to break the ignition feed between the coils and ignition module. I used the msd 8870 adapter blocks for the dis-4 to allow this. The old modules had a separate power input for the coils, so it's not needed or listed on any of the literature for the old 3.8L. (http://m.summitracing.com/parts/msd-8870)

I may try remote mounting the modules, and trying the dual module setup your testing. 0.025" gap sucks for driveability. This would also eliminate the need for the spacer blocks.