[neallewis]

At Batley indoors, the thing that will help grip levels far more than a plastic or alloy chassis is brushing the floor before the track goes down. this frequently doesn't get done or forgotten, depending on who gets to the track first to setup. If its not done, it takes a good 2-3 rounds to clean the racing line, and good luck if you end up off it. When the floor has been brushed the grip level is good and consistent. I've found the alloy chassis on the mid car fine in this case. When it's not been brushed, and on other super slippy tracks, the rear motored car can be better for sure, either with alloy or plastic. What makes Batley indoors particularly difficult (to drive and to setup) is the difference between the low traction floor and the super high grip carpet. it does take some getting used to.

My rear car has the plastic chassis, but only as I had it from a v1 kit.
I've heard of the newer harder mid gearbox being blamed for plastic chassis's breaking when used together, so I'd be aware of that.
I think you should stay alloy with the mid car, and maybe go plastic for a rear car, but run it as alloy in rear motor in the first instance. I'll be taking both (when we start racing there) and see how grip is on the day. If I get there in time, I try to push a brush round the floor before the track goes down. This make more of a difference than plastic or alloy chassis!