Heres the dimensions of 6 different 1/5 scale rigs including the XMAXX. The L x W x H measurements are all within about 3 inches or so of each other between all 6 rigs. Every company on this list states that their kit is 1/5 scale except Traxxas who doesn't tell us what scale its supposed to be...
Its longer than the Kraton 8S and nearly as wide. Both kits run on 8S and are powered by a 1250kV and a 1275kV motors respectively. They both weigh around 20lbs. Arrma calls the Kraton a 1/5 scale Traxxas's website doesn't actually say what scale the Xmaxx is but judging from the specs Id say its...
Ok, I was confused because his thread title said he was looking at 1/6 scale kits which the XMAXX & the XRT are both 1/5 scale kits. I guess I didnt thoroughly read the post where he said he was looking at the XMAXX & XRT rigs specifically
Parts are going to be more expensive. They take up even more room on your hobby bench to work on if thats a limitation for you. As far as batteries go I'm pretty sure all the 1/6 and 1/7 scale rig are 6S so your 3S packs should be fine. I dont believe you get in to 8S rigs until you hit 1/5 scale...