It's considered a 1/8 yes but I think it's more of a 1/10 scale.
Kind of puzzling actually. The drag car DR10 I gave to @WickedFog son is a 1/10 scale but it is huge.
The Arrma buggies are decent but I don't recommend the Mega version.
The Typhon V3 3s is a cool ride but if you really want to step it up then the Typhon 6s is a good one.
You posted a few really good rigs as well.
Have fun and don't be afraid to ask these guys anything.