Jez and max were both using the plates on an x-pro and an X2c on sunday at bridgford, Our track markers are pretty hard and not forgiving if you give them a good hit.
They seem pretty robust with the plates they have on the bottom and look like a good little mod, Jez has done an excellent job making them
Any car will break if they get a good hit on the front. I have broken a B4 and an X6 Squared chassis in my time, and my friend Wes has done quite a few X6 chassis recently, although he has sourced this down to a badly machined brass front bulkhead. Just be glad on the MR and X2/X2c that you can actually replace the front plate and not have to replace a whole chassis!