The STi heads can be cleaned up cheaper than you can build a hybrid block. It's not fair to compare your hybrid to a completely stock STi motor. The EJ205 heads are nice, yes, and they work great for a hybrid setup. However, you should really compare built motors with built motors, not built motors with stock motors.
It's kind of like how people like to brag about their stage 2 WRX having "STi power levels" when a much more fair comparison is a stage 2 STi...
2015 STi: Still Stock
04 STi, 04 WRX: SOLD