@Sonic - I run SpeedPower batts in mine mate. I buy them direct from HK and get a fairly good deal because of that.
The SP website also shows all the stats, including height so can choose which ones you want.
Definately advise to go for the locator lumps as without them, your batt will want to slide around too much.
Also, when you get your car, you might want to put a little bit of padding (like some servo tape) on the front bulkhead - this is where the battery sits up against it. On a heavy front impact, you can crack the hardcase of the lipo. (no biggie, as Ive done it before, but better to prevent it in the first place!)
Enjoy the Cat - awesome little buggy.
