The new 417X metal battery holders do look nice, but it looks like they also weigh a lot more than the 417 ones? From looking at the pic on Stilo's post, the 417X ones weigh a combined total of 42g. Those on the 417 only weigh ~15g.
My 417 is only a few grams over the 1350g minimum weight limit at my club, and thats with all 3 of the standard 417 battery holder in place. I wouldn't really want to add another 25g, plus maybe more weight on the electronic side to balance the car, if I change to the 417X...
