So far, I have not experienced any issues with either my 6S or 8S Kraton diffs. That being said the 6S doesn't have as much use as the 8S but so far so good. The 4S is a whole different story cuz it's a whole different rig.
As far as I can tell, the Sledge is essentially the same rig as the...
I think WF is correct. You're looking at two different scales. The kraton 6S exb is $699. The 1/5 scale kraton 8S is around 1k.
I'm not aware of any rc sites like pcpartpicker. If you're unsure just post up what your considered getting and we can try and steer ya in the right direction.
The 4S Arrma kits are garbage compared to their 6S and 8S rigs. At least the Kraton I know for sure is, and I'm assuming the others are too. The Kraton 4S is a completely different rig from its bigger brothers. If I didn't also have the 6S and 8S Kratons I would have resold my Kraton 4S a month...