I have both my DSP in cabin...i do not have any issues with, though as mentioned, both NR vs DSP are different in sensitivity, which I do not have a reg NR to confirm. Depending on the front location, overall shold do fine in reporting the source, as you might see front on occasion do to reflectivity by other vehicles, or more so by signs.
Not sure what you run into on your daily, but I only have Ka enabled on the rear antenna only. This cuts down falses by BSMs or other. If a LEO is to hit me with K or even X, the DSP on the front is adequate vs Ka 35.5 being more sneaky.