Looking for new Mini

I received my CRT.5 Pro but I'm a bit confused.

I thought the Pro kit had the extended chassis wich allows standard 1/10 servo's ?! Or I'm I wrong about this.

Either way I cannot fit my Ko2123 on it.

So whats next ? I probably have to buy RCM's extended chassis ?

I would also like to have the other part of the center diff mount in alu. Does Mike have this (I don't see it in the parts list) ?