Dragon Ball, DB Z, DB GT/SSJ4 (Baby) vs SSJ4 (Super 17)
We know that a full power SSJ4 was enough to over power Golden Great Ape Baby, but during the 17 arc, Goku got completely dominated by Super 17.
1. How much stronger did Goku get during Baby arc to Super 17 arc? Some people at Neoseeker say its multiple times stronger, but I fail to see how Goku could get even twice as strong (without any special training).
Even with near death or fighting strong opponents, the power up doesn't = to twice or multiple times stronger. The only time Goku and Vegeta got twice or many times stronger is during the Cell arc when training in rooms of spirits. Other times during Frieza and Majin Boo arcs, Goku and Vegeta only got around 15-20% increase.
There's really no place for him to have improved much at all, as there's no room for him to train, and the Zenkai power ups basically became non-existent after the Cell Saga. Even if they did exist, it would only be increases of a couple percent, not multiplying his strength several times.
Goku managed to undergo training and recoveries several times in the past where he did manage to increase his battle power by several fold.
Goku's training with Kaiou brought him from barely over 1,000 to over 8,000 (an eight fold increase)
Goku's 100x Earth's gravity training brought him from over 8,000 (uncertain as to how much, since he would have received a Zenkai from his fight with Vegeta) to 90,000, a 10-11x increase.
Goku's Zenkai from his fight with Ginyu brought him from 90,000 to 3,000,000, a 40x increase.
His increases became less and less pronounced in the later sagas, as his increase from the Room of Spirit and Time was probably less than that of his Kaiou training, and his seven years of training in the afterlife was a considerably lower increase (spent most of his time working on Ssj transformations).
During the course of GT, outside of when he has the ki from Gohan and the others donated to him, there really isn't any marked increase in his battle power, so from the fight with Bebi to the fight with Super #17, Goku should be around the same strength. If he is stronger against #17, it's not by a large amount.