The RoadRelay 4 is compatible with the ISB; however, DC decided to use a different protocol for the RAM. Rumor has it that the unit for our trucks would be released around 1 Feb, I haven't been up to my local Cummins distributor since then, but my guess is not until 1 March at the earliest. BTW it looks like the cost will be in the $1000-1100 range (installed, not a DIY project).
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'99 2500 4X4 QC/LB Blue Box, 14cm2 housing, RS9000's, VelvetRide, Line-X, M/T w/Goodyear 305/70s, boost/EGT/transmission temp, transmission pressure, AMSOIL throughout, BD valve body/TC/PressureLoc, Bosch 275 injectors
Don't be fuelish, go diesel