[Tui2]

been using the recommended factory oil, Caltex 5w-20, the last service being around the 100,000 km mark it now has 110,000 km on the clock was told to go a thicker oil from here out, opinions please?

And can I also ask, since the GT is my Dailey drive and is due for a tune, what experiences proved the best ie type of and necessary/ not necessary replacement parts, as I was quoted $2500 for an upgrade tune {not including a cat exhaust whatever that is ,I say that as it has been an issue with prior enquiries) bit did include SC pulley, spark plugs, and water pump plus whatever turns 335kw into close to 400kw which I truly believe unnecessary fo Dailey drive?