http://www.youtube.com/watch?v=z1aIGSfwWPE
Since a couple months now, the Ifrit and the Hunter have shown much higher-than-expected damage resistance for their engine blocks.
It takes about 3 direct hits on the hood, radiator, or headlights to get them to fully explode, while a hit on any other part will result in immediate destruction. Striders do not seem to suffer this, as a direct hit will destroy them no matter the hit location.
Additionally, the Ifrit has another problem. When directly in front it, at about 50m, if you lock and fire just a bit above the locking icon, the missile will airburst just a few centimeters away from the windshield, instead of allowing a direct hit. I think an easy solution for this would be to move back the lock-on point by about 0.5m to allow the missile to get a direct hit. {F25159}