I'm gonna throw a spanner in the works now..
I have two x6 sq's and out of all of my cars they are the easiest to drive and own. Mantinence is easy and parts are cheap enough. The wing mounts are made with a softer plastic so arn't a problem anymore and eveything else is bomb proof. One of the things I like the most is how easy and fast it is to change rear toe and anti squat.
Now the thing is to convert to an X6 can be expensive. Yes the kit is cheaper but you still need other bits to get the best out of it like Hangers and the longer axles so you can add an extra £25 there. BUT you can get a second hand x6 sq with all those bits and losi shocks for £150 or less so I'd keep the B4 as it is, buy a used x6 and use whats left of you're budget to buy electrics, then you have the best of both worlds
