I had good luck with a torx driver on the rounded heads, it still had good grip on them. It us worth a try before drilling them out, or try a special tool for striped screw heads.
I just looked on the trade4me site, and can you tell me why you think the rtr buggy is a good deal and the truggy is overpriced? 259 for the buggy and 249 for the truggy....
This might be what you are afterhttp://hobbyking.com/hobbyking/store/__46363__XT60_to_HXT_3_5mm_Connector_Battery_Adapter_compatible_with_Walkera_QR_X350_2pcs_bag_.html
But have a good look on all the connectors
Remove the ear on the outside of the battery holder and also the screw in the middle of the side guard and the notch on the side guard that holds that screw.
(don't remember if there are picture in this thread, but I know there are in the first 2 post in the thread on rcgroups)
Hmmm it is the only comment on the picture he shared from the lcracing-emb Facebook page. This comment isn't on the lcracing-emb page but on Sun Ben's own page.