Usar 5W/30 en ese auto está bien, mejor ahora que estamos en clima frío. Respecto al Toyota Motor Oil, si lo vende barato el concesionario y no dice "sintético" por ninguna parte, lo mas probable es que no sea sintético (en algunas partes lo he visto catalogado simplemente como mineral).
No conocía bases que dieran W30, pero esto dice Toyota:
Genuine Toyota Motor Oil
Formulated with a special additive package that helps protect Toyota metal and gasket surfaces from corrosion, prevents foaming and maintains the proper application of oil on cylinder walls.
• Available in 5W-30, 10W-30 and 10W-40 grades
• Four-point depressants maintain fluidity in cold climates
• Viscosity index improvers stabilize viscosity levels for a wide range of operating temperatures
Synthetic Motor Oil
Many new Toyota models are certified for a new, zero weight synthetic lubrication standard, or 0W-20. This lower viscosity oil pumps better when cold, yet provides uniform lubrication, reduced friction and better overall efficiency than conventional engine oil.
• Improves fuel economy
• Improved thermal stability
• Longer oil change intervals