I know that there are needed variations in the mods for the 3910, meaning that you cannot transfer them from the 2900 to the 3910. I think John Tucker was genuinely surprised that the 3910 outperformed the 2900. He, of course, had no choice but to change to the 3910 as the 2900s were no longer available.
I have yet to receive the Exemplar 3910 and it too will take a long time to break in. 711Smilin may want to better answer your question on the benefits of the modified 3910.
I have yet to receive the Exemplar 3910 and it too will take a long time to break in. 711Smilin may want to better answer your question on the benefits of the modified 3910.