Looking back, I am very confused. is that panel to the front of the case or just to the HDD enclosure?
With the HDD orientated front to rear in the case as your post #11 they will get cooling from the front fan and there's no need to mod the case per-say unless grill induced noise is becoming an issue. The comments about not using too many fans inline still stands.
If however the 80mm fans can be positioned away from the 120mm ones and are mounted on the HDD enclosure itself, then this could be beneficial, provided they are far enough away from the 120mm front case fan.
Clear as mud? Time for bed methinks.
