Even though it's pretty old, the current Sienna has plenty of poke and fantastic resale values. But a transition to the TNGA platform could make the successor model a class leader. These are the first true spyshots, the one earlier sighting being of a test mule. However, that thing did tell us that Toyota was planning to make a wider and longer minivan, thigh which would be impossible to notice on this prototype.The styling that's peaking out from under the camouflage is sporty, probably quite similar to the 2019 Camry or Avalon. You've got quite bold rocker panels, narrow headlights, large wheels and a massive grille at the bottom. It's still a big box on wheels, but it's a modern box at that.We also assume that the TNGA will make the Sienna surprisingly good in the handling department, much as it did with other Toyota models. But despite the architectural change, the foundation of this car will likely still be a V6 engine, most likely carrying over with some power delivery tweaks or uprated economy. Toyota hates turbocharging as much as Mazda.Given the reputation of the brand, we also would be surprised to see a hybrid Sienna, something people have been wanting for many years. It's probably not going to be a plug-in like the Chrysler Pacifica , though such a setup could eventually be developed.The interior should be a rather nice one, as Toyota isn't afraid of offering Lexus levels of quality. Expect better materials on the dash, new screens, and top-of-the-line safety. Also, some extra convenience features wouldn't hurt, at least on the high-grade models.