I had the version for iOS and I bought the Superboy since it's a "must-have" character and the Coin-Doubler" to make more money. Even then it was a lot of grinding to pass stages. I stopped playing until upgrading became close to impossible since some rare parts were required to upgrade and the stages became extremely difficult to pass. I had all my characters 99% upgraded.
Seeing this MOD I decided to have another try. If you don't advance the stages you'll keep opening the suitcase to get 1-2 diamonds or cash (from 20 up to 200). You can open one every 3-4 seconds so to make enough money to upgrade all your characters you'll have to spend a good amount of time repeating that step.
To make it worse, I decided to upgrade two characters and finish the 2nd stage until I could get the Superboy. With this hack, you can't get it since it requires real-money and even if you want to spend, you can't do it do to the hack. To make it even worse, after some beating some stages you don't get a diamond or cash after opening the suitcase. You'll get plenty of parts. I don't know if passing many stages it'll improve to 3-star parts but after getting to the end of the 2nd stage, I get 1-star maximum parts instead of the constant diamond/cash. You do get diamond/cash now and then but when you get parts, after ~12 parts your backpack gets full and you have to sell or adjust your inventory, wasting more time. So you can't keep mining for that extra cash by just pressing two buttons every 4 seconds. And the parts you can sell for measly $12.
So my recommendation would be to mine as much as possible before you start beating the stages. I'll see if using an auto-clicker is possible. Maybe it can be automated. Leaving the app running for a day or two might be able to make enough money and diamonds before starting this game.
Thanks for sharing this hack. The game would be more fun if it wasn't pay2win.