The Colossals are mix kits (Plastic/Resin with some White Metal bits). I could actually see someone "borrowing" the Menoth Colossal to use as a knight titan. As for their size they will make most 40k vehicles look smaller. PP commented that the Conquest (Khadoran Colossal) that its as wide as the Legion of Everblight battle engine is high (somewhere between 6 and 8 inches). As they go on a 5 inch base and most of the pics/art make them look as though they are going to be hanging over the only 40k vehicles comparable in size are things like the Stormraven, The Monolith, or possible even a Baneblade.