Those Lipos seem good value. Although not BRCA approved these are also worth a look as they are highly regarded:
http://www.ebay.co.uk/itm/Turnigy-Na...item4ac200a72f
On the esc front, a 120A esc is advisable when running a 5.5/6.5T motor - especially in a 4wd. The Fusion combo is good for the money, but a mate of mine has been through a few of them in his 2wd buggy.
I can certainly vouch for the Dualsky escs. The new 870 is brilliant
On the second hand market, a Speed Passion GT2.0 pro is a good buy. They will take a 4.5t, are very smooth, reliable, and come with a nifty programming box.