That's good to know. The plastic outdrives are around 10 € here, while the alu is 20 € and the steel is 30 €. I guess with either of them you will just change blades only. I wonder if this is cheaper in the long run.
best to go with steel outdrives at front as it would last longer thus, cheaper in the long run. Have used alu outdrives before since steel was hard to get at the hobby shop, still bends (though minimal) with medium/hard impacts and I'm only running 17.5 blinky. Spec R has really strong and good steel outdrives for the xray platform that doesn't even require you to use the blades (if you are looking for a cheaper alternative).