I have an A903 and no intention of changing it at the moment. I just would like a little feed back from people who have gone that route. And those who decided not to.
I have a gear vendors unit and I really like it. It’s behind a slightly built 273 with a 904 and 8 1/4 with 373 gears. It definitely makes long drives more pleasant. At 65 mph runs about 1800 rpms.