Hi,
The whole brace thing on the back is exactly the same as on the XX4 as you're using all XX4 parts except the chassis which is identical at the very back to the Losi one. As Gayo says, blame Losi
To back up what Paul says, use XXX (doesn't have to be the BK1 ones) rear inner hinge pins and you can fit an e-clip on either end, I did this when I built mine and they have never come off so my nice blue brace still looks good as new
The front brace is the B2/B3 one not B4 one. Our local club shop guy did have some for £1.50 I think, I can send you one at cost if you like, will see him next on 7th Jan. In fairness to Chazz, I don't believe he claims to include any of the new parts with the X5 kit.
I built my current car from a complete kit from Chazz at the start of the year and it's still practically like new. Obviously I've replaced a few things over the year but a new built X5 should last ages!
Any other questions about the build, let us know on here.
Where do you race?