Well, considering a fact that you need that 150 M, and that you could save some real money and build arena which would give you more profit, or to buy some good players and strengthen your squad, how can it sound bad ?
I'm not sure what the difference would be between those two cases in training. There are people here who can actually measure it, and I hope they could tell you. But I guess it's not a big difference. You need some kind of strategy for your team, what to expect in I (or II ) league, do you have a lot of quality youth to train, do you need strength, or you need a way to collect profit faster.