People seem to have such limited memories....
VW have followed the same pattern for a while when it comes to new model releases:
Announce new base models in Summer (usually June/July) (Not GTI, Not R)
Orders start August/September
Deliveries start arriving end of year.
GTI announced following year, orders in June/July, deliveries start towards end of year
R announced Spring (March) following year, orders April/May, deliveries August/September
So GTI not announced until 2020, and you wont get em towards end of year
R wont be announced till 2021, and you wont get that till 2nd half of year
As for specs - usual form is to start rumours of some silly figure (like all the rumours of a 300bhp GTI for the MK7 and now 400bhp for the Golf R Mk8)....reality is usually halfway between current power and the rumoured power.....the rumoured power being closer in some special edition (clubsport or performance) some years later
Buy now, as you will be waiting almost 2 years before a GTI mk8 physically appears on your driveway.....with a fair few glitches that need to be revised out.