It sounds a little odd to say that the new 2019 Forester will arrive at Australian dealers in September of this year (2018). But that is due to the way Subaru name their model releases. The next Forester is the MY19 or 2019 model of the Forester—even though you will be able to buy one in 2018.
What we know for certain now is that the 2019 Forester will only have the one engine. The totally new 2.5 direct injection naturally aspirated petrol boxer motor. No diesel and no hybrid. Not initially anyway. There is some talk of an electric hybrid that might turn up in late 2019. Also, one review suggested Subaru's new 2.4 turbo engine might also find its way into the Forester either late 2019 or early 2020.
For the time being, this new 2.5 petrol engine puts out 182-hp or 135-kw ... if you prefer kilowatts. This is a useful 12-hp, or 7 percent, performance boost compared to the 170-hp obtained from the older 2.5 boxer. While I cannot find any 0 - 100 timings in any of the available reviews, reviewers do comment that this 2.5 Forester is noticeably quicker than the model it is replacing.
This engine is reported to deliver economy of 7.12 litres/100 kilometres on the highway, which is very close to 40 miles per gallon (using Australian gallons).
However, I for one find it sad that the class-topping 2.0 litre dual-scroll turbo 250-hp power plant will not be carried through in the MY19 Forester.
It also seems that there will be no manual transmission model. The only transmission will be an automatic transmission and is Subaru's award winning CVT. One review that I found reports that the CVT being used is the high-torque CVT which was only available previously in the XT model. I hope this is the case as the high-torque version of the Forester CVT is certainly a better transmission than the standard CVT.
The other bit of information I gleaned from hunting around the Web was that three new colours have been made available in the US, and can reasonably be expected to come to Australia as well. These are: Crimson Red Pearl; Horizon Blue Pearl; and Jasper Green Metallic.
As an aside: Apparently this is Forester's 20th year in Australia.