a123 6.6v questions

[ClodMaxx]

so i just took the plunge and ordered a pair of a123's 6.6v 4600mah battery packs and their hypersonic charger. my question is this to anyone that bought similar packs from a123: is there anything special i need to know? i guess i'll find out how they fit in my battery trays (they'll currently hold 8 sxs ni-mh cells) and i ordered some velcro straps to hold them down.

will it really charge in under 15 minutes? do they stay in balance as well as everything i've read? i don't plan to run a LVC - they should drop, and drop quick, at the very end. a good visual cue to stop running.

any insight on my new purchase would be appreciated.