Thank You ALL who gave your advice on my E strater dreams............All your comments make sense and I will stay with the stock 400/Gearbox combo.
I will check on the ESC which is NOT a GWS part and start off with a 3S LiPo and see how it goes.
Actually this is my 'come back' to RC after an abscence and Im trying to get my young nephews into RC flying.

Incidentally, my reference to 'weenie' performance from the brushed motor is from my first experience with electric flights back in ( gasp! ) the eighties, with 05 can motors and lead heavy 7-8S Nicads. I had scratch built a 5 oz British design called an "Electric Haze" and we just managed to crawl around the sky and plop down at the end of the Battery.
run. It was a nice looking plane.

But golly, looking at all these great stuff available today, I'm jumping back in to electric flght.
I might even re-visit my old Electric Haze.

Cheers you guys and look out for me out here asking all the 'dumb' questions OK.