IMO the best of these is the Xray, hands down. Of course the Associateds can be run as well - although the TC4 is of limited use, depending on what class you want to run. However, modern touring cars usually don't have "secure compartments" for lipos. Mostly they are just strapped in, by sticky or velcro tape (it's important to not fix them too rigidly, otherwise they would affect chassis flex). And these tape mountings might get in the way, if using non-bullet connector type batteries. Any special reason why you don't want bullet connector on your lipos?