Not gonna make a long thread about this. The upgrade system can be greatly improved by making 2 easy changes.
1. Remove the -1 on Fails..... It was never like this on TW.
2. Remove the possibility of +1 in purple/green. They literally cost 10x the price of blue/red and should give at least the possibility of +2. And make the posibility of getting +2/+3, 50%/50%.
These changes would greatly improve the system for everyone.