The gp batteries are good. The ibc batteries are good. Never ran ibc but the specs and every one else says they good.
It takes a good soldering iron for batteries. I bought a 100 watter just for batteries. A little bit of ca glue should help with keeping battery on the other cells. It is not hard booda for soldering batteries. Just patients. Here is a site to help with decision on to make or not to make.
http://www.rccaraction.com/rc/articl...ld_battery.asp