6000s won't be legal (5300 max IIRC for BRCA) and max dimensions are 69.5 (x2) by 47 by 25.1
I would personally advise against buying something like LiPos abroad as it can be a real pain in the butt if you have to ship back and prove you didn't cause the issue.
Have a look at the selection at JE Spares
http://www.jespares.com/electric-mod...tegory_id=1168
Quite a choice at £70 ish and remember they are offering the discounts at the moment. There are other choices out there for similar money too ... but they don't come as standard with the best service in UK RC retail
