On Level 20 towers will no longer require the normal resource (Solid Bronze), but instead will demand Research Guides. This will increase the quality of the tower.
| Tower Quality | Research Guides | Expert Research Manual |
|---|---|---|
| Common (Level 20) | 30 | |
| Excellent-1 (Level 30) | 100 | |
| Excellent-2 (Level 40) | 200 | |
| Elite-1 (Level 50) | 400 | |
| Elite-2 (Level 60) | 800 | |
| Elite-3 (Level 70) | 800 | 100 |