There is no real visible difference between the two. Just small changes for strength in the upper rear bulkheads rear camber bridge steel diff gears, diff cases and the number on the box. I have the original kit and it works for me. Key tips, clutch build, gear alignment and mesh, and some type of brace. By the way I am trying to find a 4 mm chassis and all I see is the high traction chassis from mugen which I have, the Arena which is 3.3 and cso which is 3.2. Anyone tried these other chassis? I'm not completely satisfied with the high traction chassis even though it's better than the original.

hi nitto at nsw titles the car next to us ran a nack chassi //futarbo pro we ran an evo and it bent just like /mugen from the brace back but I bent back we tried arena I think but non are any better than the kit on witch is not mutch good if you hit anything
greg

Thanks Greg , I'll try to get that knack chassis

I donot know if the nack one is any better than the others
greg

Hi guys.
I need stiffer springs than the kit ones and I cannot find any mugen spring chart..

if I rember //light blue/dark blue/grey/white//in old ones yellow/black
greg

Right now I'm using gray in the rear and dark blue front. Both are stiffer than stock. The whites are a little too stiff for me.

So the whites and greys that we are using in mrx5?

Oh yeah that's correct

Greg, all chassis will bend, we found the Knack chassis stronger than either of the two Mugen chassis. Mainly because it's stronger between the engine and rear bulkhead supports, it has a slightly larger profile making it a little stiffer with only 3gr weight penalty. This is the second Knack chassis we have used with the first only changed because we were running in the Nationals not because it was bent. I would recommend this chassis as an excellent option to either of the Mugen chassis.

Mazda, could I purchase this chassis anywhere else besides pro futaba or knack racing? I'm looking for an easier website to order from.

Rich u need to order an X Ray.

the xray is just a copy of 4r so why go backwards and some of the parts fit cap
greg

I had a mtx4 and the x ray is way better and the cap came out after the X ray. But u can't lose with either one. The only good thing from mugen is the 8 scale.

I can't dispute the fact that the X is a great car that works, and I get that point, but I'm not ready to throw in the towel just yet. When I do, the X is the obvious choice especially knowing that u guys have great deals at Fordam Hobbies.!!